Phd Candidate Herman Margaux
email: margauxherman@hotmail.com

Bertrand Hirsch

Säblä Wängel, the Queen of the Kingdom of Heaven

Starting from a general consideration about the Ethiopian queens from 16 th to 18 th centuries, I have come to focus on Queen Säblä Wängel, a notable figure of the royalty of the 16 th century, and on her royal foundation called Mängəśtä Sämayat Kidanä Məhrät.

This paper is based on an analysis of a corpus of composite sources. We will compare the statements explaining the history of the construction of the church in the sources written after the death of the queen to the records produced when she was alive. Our purpose is to have a better understanding of the 16 th century's reality.

Nowadays oral traditions associate Queen Säblä Wängel to the history of East-Goğğam. She is currently known as "the Queen of Mängəśto", the name given to the area surrounding the church Mängəśtä Sämayat Kidanä Məhrät, which literally means "The Kingdom of Heaven". It is dedicated to Mary described her as Kidanä Məhrät "The Covenant of Mercy" 1 . Säblä Wängel is in fact considered as the first founder of this church which is located in East-Goğğam, in the district of Ǝnnämäy, between the rivers Suḥa and Yäbärt, not far from Bəččäna and Däbrä Wärq 2 .

Queen Säblä Wängel, called Wänag Mogasa, was the consort of King Ləbnä Dəngəl, called Wänag Sägäd (r.1508-1540). During his reign the political center of the Ethiopian Kingdon was at that time located in the province of Šäwa. The reigns of Ləbnä Dəngəl and his sons and successors, Gälawdewos (r. 1540-1559) and Minas (r. 1559-1563) had seen significant changes. Among other things, the period marked the beginning of direct contact between Ethiopia and Europe. Under the pressure of the Muslim invasion lead by Iman Grañ Ahmed (and later by his nephew Nur), the country opened voluntarily its doors to Europe, especially to the Portuguese. This was also a century when unchristian populations of nomad pastors, the Oromo people, came from the southern periphery to settle in the borders and then in the center on the Christian Kingdom

3

. Facing this mix of population and religion, this century was a time of questioning and changing. It was in such chaotic political context that King Ləbnä Dəngəl (1508-1540), and after him, his two sons, Gälawdewos (1540-1559) and Minas (1559-1563), and then his grandson Śärṣä Dəngəl (1563-1597) had to rule. By their sides, Queen Säblä Wängel was a witness and an actress during these times of crises. She married the king some time before 1518 4 , and died around 1568 5 . Thus she saw her two sons and one of her grand-sons reigning.

In an article published in 1994, Tadesse Tamrat states: "Mängəśto in Ennä May virtually 6 became the center of the kingdom with the political heartbeat of the country being felt at Säblä-Wängel's court of Mängəśto for much of the second half of the 16 th century"

7

. His analysis is mainly based on a History of Goğğam written by Aläqa Täklä

Iyasus in the beginning of 20 th century. The purpose of our paper is to have a deeper investigation on that subject to understand what kind of "center" Mängəśto was. Is it a late construction or a 16 th century's reality? We want to compare what History remembers about it to what we can prove. This is an investigation on the links between Säblä Wängel and Mängəśto, and on their role in the 16 th century's Ethiopia.

First we will analyze the sources in our possession. We will present the manuscripts found in Mängəśtä Sämayat: two Tarikä Nägäśt, one Nägärä Maryam and some texts found on separate folios. Next to them we will introduce the work of Aläqa Täklä Iyasus. It will also be necessary to focus on the texts produced at the royal court in the 16 th century, when the queen was alive. The first questions we will try to answer are the dating of the foundation and the reasons that make Säblä Wängəl come and settle in East-Goğğam. Was the church built during Ləbnä Dəngəl's reign in the native region of the queen, as stated in the modern sources? It will deal with the identity of the queen and the contemporary stakes of a settlement in East-Goğğam. In a last part, we will try to It is not a history of the rulers through a traditional list of kings, reign after reign. Indeed, the central topic of this book seems finally to be the province of Goğğam. The purpose of this narrative is to depict the region as integrated in the Ethiopian Christian Kingdom since its foundation. The first part of this manuscript is all dedicated to this purpose (f. 1r-8v). The last part of this manuscript (f. 9r-15r) is dedicated to neguś Täklä Haymanot, the different lords of Goğğam and the history of the province during the 19 th century 13 .

Finally, it could be assimilated to a sort of regional Tarikä Nägäśt as it is dedicated to King We had also access to one Nägärä Maryam, measuring 28 cm high and 21 cm large. On the last four folios, there is the history of the church's foundation produced in 1887 when neguś Täklä Haymanot of Goğğam decides to rebuild the church 29 .

Next to those three manuscripts found in Mängəśto, there are some separate folios. They are grouped together in 6 unbounded quires. Some of them are exactly the text that we found in the History of Mängəśto. For example, the text of the two first quires of separate folios is the same as the one found in the four first folios of the History of Mängəśto. The handwriting looks similar as if it has been written by the same person 30 .

The text of the four first quires of separates folios is to be compared with the first part of the History of Mängəśto. The text of the fifth quire is the text of the church foundation made by Täklä Haymanot that we found at the end of the Nägärä Maryam. The text of the sixth quire is totally independent: we did not find any similar narrative in the manuscripts of the church that we were allowed to see. It had been written in 1969 for the commemoration of the late Princess Säblä Wängel Ḫäylu who had just passed away.

In the church, they could not inform us about the name of the copyist, or the time of the copy. . In the Tarikä Nägäśt, the royal couple blesses the church whereas in the History of Mängəśto, the place is already blessed, and by this way attracts the rulers of the kingdom.

Still, these both books attest that this church exists since Ləbnä Dəngəl's reign, and the first one clearly states that Säblä Wängel built it, like all the sources produced in modern times.

To have a better understanding on the foundation, we have to analyze the sources two churches were situated in East Goğğam. Säblä Wängel was a young queen and her main function at the court at that time was probably to give successors to the king.

Building a church during this period seems then difficult to achieve for Säblä Wangel.

If Gälawdewos's chronicles remark that Säblä Wängel is the only wife of Ləbnä Dəngəl, nothing is said about the church or the area. The only church foundations recorded in the official chronicles are related to the king, when he decided to build Tädbabä Maryam and Mäkanä Säma'ət

61

, both in Amḥara.

Going through the reign of Minas, new details are found on this place. The chronicle says that Minas was established king in the region of Mängəśtä Sämayat, where the queen was, and that he went there to meet her [START_REF] Pereira | [END_REF] . The chronicler says that Minas came during the first month of his reign to Mängəśtä Sämayat, from where he left with his mother. We can conclude that Säblä Wängel was in Mängəśto in 1559. It attests that the foundation was linked to her before the reign of Minas.

The first pages of the chronicle of Śärṣä Dəngəl record that it was the residence of the queen: « Alors commencèrent les plaintes des principaux du peuple. Lorsque ceux-ci arrivèrent où se trouvait la reine Säblä Wängel, car en ces temps-ci sa demeure était à

Mängəśtä Sämayat » [START_REF] Rossini | ወእሜሃ፡መጠኑ፡ነጐርጓረ፡መላሀቅተ፡ ሕዝብ። መሶበ፡ በጽሑ፡ኅበ፡ ሀለወት፡ ንግሥት፡ ሰብለ፡ ወንግል፡ እስመ፡ ውእቱ፡ ጊዜ፡ ኮነ፡ መካነ፡ ሀላዌሃ፡ በመንግሥተ፡ ሰማያት።[END_REF] . This is the first mention in the official texts of the 16 th century which links definitively Säblä Wängel and this church. This is clearly the residence of the queen.

Thus we can conclude that Mängəśtä Sämayat was the residence of the queen in the beginning of Śärṣä Dəngəl's reign, in 1563, and that it was already there that Minas came to meet his mother in 1559. We do not have any element that can attest of a construction of the church by Säblä Wängel during Ləbnä Dəngəl's reign.

The chronicle of Minas says that Säblä Wängel was living in Äyba when Minas returns from his captivity in 1541 [START_REF] Kropp | [END_REF] . A record found in the chronicle of Śärṣä Dəngəl states that in 1590 the king decides to transfer his residence from Gubä'e to Ayba 65 , the place that is chosen between all the lands of Wägära by Säblä Wängel when Grañ was killed in 1543. The chronicler adds that she built there a royal camp (kätäma) which still exists at that time 66 . But that does not mean it was the only place where she used to live.

If the chronicler says "kätäma" that can also be to distinguish it from another residence.

Thus there is no evidence of Säblä Wängel's settlement in Mängəśto before 1559. But there is no proof that she was not there already and we can think that she was living there in 1559 when her son came to meet her. Let us compare these statements to the sources produced during the 16 th century to search some clues about her native region.

o An obscure background -"Goğğame" or not?

The chronicle of Gälawdewos, translated by W. Conzelman 74 , describes the religious ceremony for the union of Säblä Wängel and Ləbnä Dəngəl and shows the Holy Blessings that they received. The chronicler states: « elle oublia son peuple et sa famille. » 75 . It implies that she is issued neither from the traditional nobility nor from a people which is integrated in the Christian kingdom under the authority of the King. This attests that this union is in reality a dynastic and political alliance. We are then faced to three different possibilities which derivate from the status of Goğğam in the Christian kingdom at that time. If she is native from Goğğam, the region is then not a province ruled only under the government of the Ethiopian kingdom at the beginning of the 16 th century, but a region governed by its own rulers with partnership agreement with the Ethiopian kings. On the contrary, if the region is really integrated this means that she is not native from there. But it can also mean that not all Goğğam is Christianized and that she comes from a part of it that has not been yet integrated in the kingdom. At least, we can conclude that she is not from Šäwa, the region of the kings. We will discuss later about the situation of Goğğam in the geopolitical context of the kingdom to determine if she is or not native from this region.

-Is she a Falaša?

Who were her parents? The chronicle translated by M. We found another mention. J. Bermudez relates in his Travel's relation the event that happened to him and to Portuguese in 1542:

« Further that, that territory (the Hill of the Jews) belonged to the Queen (Sablä Wängel), and that the tribute from it alone was sufficient to maintain the army for five or six month. » [START_REF] Whiteway | The Portuguese expedition to Abyssinia in 1541-1543 as narrated by Miguel Castanhoso with some contemporary letters[END_REF] .

The Portuguese arrived in 1541 and began to fight in the North of the country, in Massawa. After the first battles, they tried to find a safe place to rest. Finally according to them, and especially to J. Bermudez, they settled in a land hold by Säblä Wängel as she is said to get from those lands comfortable incomings. They spent there the rainy season with the queen. Did she receive a tribute due to her personal heritage? Was the tribute given to her because of her royal family ties?

This place is called by the Portuguese the "Hill of the Jews". It is a bit difficult to know if they are talking about the Jews as Falaša, or if the Jews are referred to the socalled "Israelites".

If "Jews" means Falaša, it is in accordance with what we demonstrate before. Yodit, Queen Säblä Wängel's mother, was the wife of the ruler of the Falašas. Then it could have been a possibility for Säblä Wängel, the daughter of Gedewon's wife, the ruler of the Falaša, to have some lands in Səmen. Whenever this union happened, it will have been for the king a good alliance. Marrying himself to the step-daughter of the ruler of Səmen, or encouraging the union of his step-mother to Gedewon was strategic. In fact, Səmen was the main stage [START_REF] Conzelman | [END_REF] between the political center of the Kingdom in Šäwa and the northern region of Šire and Tigray which were harassed by the conflict with the Muslims.

It is then strategic to conclude some trustful alliance with this region. It is effectively there that King Gälawdewos joined his mother and the Portuguese in the outset of his reign 84 .

For all of that, if "Jews" refer to the "Israëlites", the debate on her origin is still going on. The "Israelites" are for Ethiopians the descendants of Menelik I who are imprisoned in amba Gəšen 85 . As there was no rule of primogeniture, all males were equally candidates, although the proximity to the late ruler was clearly an asset. To hold these conflicts, the kings devised the institution of the royal prison, where the sons, the brothers, and the nephews of the king were confined in and known as the generic terms of "Israelites". Until the 16 th century, this prison was located at amba Gəšen in the dynastic heartland. Our purpose here is not to say that the Portuguese were in amba Gəšen. Firstly because they were not in this area, secondly amba Gəšen have been destroyed during the Grañ's invasion [START_REF] Kropp | [END_REF] . Nevertheless there is still a possibility that the royal power changed the place of this "royal jail" for a while. But it seems difficult to believe that Queen Säblä Wängel gave the hospitality to an entire army of hundreds soldiers in the vicinity of this royal amba inhabited of potential successors. It could be seen like a "coup d'état" for the new king (who was not there) and for the officials of the kingdom. At this time, the Portuguese have not met the king yet. Indeed, since their arrival they were welcomed by the queen because they arrived from the north side of the country. Säblä Wängel was in this area since the end of her husband's reign, who in fact died in Däbrä Damo [START_REF] Whiteway | attests that she was imprisoned there for almost four years[END_REF] . Gälawdewos was himself in Šäwa. For a while she took his place in his role of diplomacy and military ruler.

On the other hand, we can still wonder if this name of "Hills of Jews", with "Jews" taken in the sense of "Israelites", has been given to other places inhabited by members of the royal family. Then the fact that she got the revenue from this place is not to be considered as information on her geographical background or attachment, but more generally as a land which belongs to the royalty.

It is difficult to conclude on her background considering the text produced when she was living.

 So why choosing East-Goggam ?

o A policy of integration still going on during the 16 th century D. Toubkis comes back on the idea developed in the previous researches which concluded that Goğğam was from the beginning of the 16 th century integrated in the Christian Kingdom

88

. The steps of this integration were described as a first conquest led by King Amdä Ṣəyon (1314-1344), of a region inhabited by Agaw population, followed by policies of conquests and evangelization and finally achieved at the beginning of the 16 th century thus assimilating the region in the Christian kingdom [START_REF] Toubkis | [END_REF] . D. Toubkis confirms that the process of Christianization was going on. He analyzes the names of the different Goğğam nägäš, who began to be Christian during the reign of Bä 'ədä Maryam He also demonstrates that the kings do not have a strong authority on it

92

. He finally concludes that the integration of the territories which cover the actual Goğğam will not be completed until the 17 th and the 18 th centuries. The capital of the kingdom was fixed in Gondar in the 1630's, which positioned Goğğam closer to the central power established in its capital. The Nile stopped to be a barrier and began to be more "central" in the Kingdom as it used to be at the outskirts [START_REF] Toubkis | Aux confins le feu, au centre le paradis », Qoma Fasilädäs, un monastère royal dans l'Ethiopie du 17 e siècle[END_REF] .

Nevertheless the kings were interested in developing their authority in this area and in creating a royal network to control it in the 16 th century. The Christianization began by missionaries' activities in the 15 th century. Some small bridges and alliances were already made between the Goğğam nagaš and the kings. For example, from his childhood, Eskender, Bä'ədä Maryam's son, have been entrusted to the ruler of this area, the Goğğam nagaš Anbäsä Dawit [START_REF][END_REF] . This fact attests that the Christian king was on good terms with the local ruler.

At the beginning of this century, two different queens, grand-mother and mother of Ləbnä Dəngəl, chose the region of East Goğğam for their foundations. Ǝleni built Märṭulä Maryam in Ǝnnäbse and had many lands in Goğğam . Maybe that is one of the reasons which brought Säblä Wängel to settle there, following the two previous queens.

o The coming of Oromo people in the region gives the alarm

In the second half of the 16 th century, an event pushes the rulers to watch over this direction. Their kingdom was seriously weakened after the Muslim invasion. It was not able to prevent the migratory waves of the Oromo which began by entering in Šäwa and then penetrated in Goğğam

98

. That may have put the Christian kingdom in a hurry to increase its settlements in this part of the country. Leaders could have seen as a necessity to affirm themselves physically in this region. Firstly, to follow the politics began by their predecessors but also probably in reaction of the coming of the Oromo people, who were apparently not ready to pay their allegiance to the Christian king. At that time, they are described as invaders and pastors in the official sources. The Goğğam is full of water as many tributaries of the Nile flow everywhere, and makes the land fertile.

It would have been considered by the royalty as a disaster if the region would pass under the Oromo authority. So maybe the coming of this new population reinforced the will of the central power to increase its physical presence in Goğğam by building royal foundation.

Until now we discussed about the dating and the reasons of the settlement of the queen in Mängəśto. To conclude, we cannot exactly date the foundation but the arrival of Säblä Wängel in Mängəśto happened before 1559 during Gälawdewos' reign. We did not succeed to know where she comes from. But we can attest that she was not from Šäwa, that she had family ties with the Falaša of Səman through her mother Yodit and possibly from Goğğam as it cannot be considered as totally integrated in the royal kingdom in the beginning of the century. She was probably following a royal policy of settlements in East-Goğğam that began in the beginning of the 16 th century: two queens built there their churches. This choice can also have been influenced by the settlement of new comers in the area.

 An Ewosṭatewos' center with a strong political attribution

We will now get interested in the parts of this church in the working of the kingdom. We will try to define the role of this royal foundation during the time of Säblä Wängel, and understand what parts it played in the religious context and in the politics of the royalty during the second half of the 16 th century.

 Mängəśtä Sämayat, an Ewosṭatewos' center in East-Goğğam

Let us discuss about its first duty: its religious function. What represents this church in the religious sphere? Nothing is said in the 16 th century chronicles on the religious position adopted by the queen and then attributed to her church. Was she following the traditional church of Däbrä Libanos or the minor one represented by Ewosṭatewos?

After the Queen's death that happened in 1568, two centuries of silence are to come. The church disappears totally from the official sources. located in the west of Lake Ṭana, up north West-Goğğam, is described to believe in a particular religious school followed by both people of Q w ara and Goğğam: . For a second time, the succession appears to have happened in Mängəśtä Sämayat. She kept him with her for some time. But there was a strong opposition to his reign. She was probably not the only one who had the power to choose the king. This resistance forced her to help the young king of 13 years old to flee All these elements confirm that she was a very influential character of the royalty of the 16 th century. She was active during the successions. The Queen showed her ability of diplomacy by negotiating in 1541 the return of her son Minas, who had been captured by the Muslims almost three years before 121 . She was at that time in Ayba where she built a kätäma (a royal camp). She was thus already an active member of the royalty and the fact that she built there a camp attests, amongst other things, of her great authority since the death of her husband in 1540. Later on, she is the one to whom the death of Gälawdewos is announced, before Minas ascends the throne while she was in Mängəśto 122 . Then during the succession of Minas, she acted strongly to push her grandson Śärṣä Dəngəl on the throne as another branch of the Solomonic's line tried to come over him. Finally she imposed her family and only one branch of royal kings ruled, all sons or grandsons in direct line of King Ləbnä Dəngəl and Queen Säblä Wängel.

« A cette
Amongst others, the lords of Goğğam were actively involved in the succession, and tried to impose their own choices against the designated king

123

. The presence of this royal foundation in the area was maybe a way to gain more control over them.

The majority of the mentions of the official chronicles related to her foundation appeared during the successions of Minas and Śärṣä Dəngəl. Now as these texts were dedicated to the kings we cannot take them as simple descriptions. And as it is presented in the chronicle, she executed her actions from her own residence. Mängəśtä Sämayat became the recognized residence of the queen under Śärṣä Dəngəl's reign and the place where his succession and the previous one happened, the place of the power of Queen Säblä Wängel. We can thus see the influence of this place in the working of the royalty. It reflects the power of this Queen. From the death of Ləbnä Dəngel until her death, she was the one who made the kings. To conclude, Säblä Wängel is one important decisionmaker of the royal power which placed Mängəśtä Sämayat, her residence, as one of the political center of the kingdom. It was the place to be to ascend the throne. If one of the duties of the Queen when she marries a king is to give a successor to the dynasty, Säblä

Wängel fulfilled it with success from Mängəśto. That is why we can consider Mängəśto as one of the political center of the country, maybe the first that had been created in Goğğam.

Conclusion:

It seems that Queen Säblä Wängel and her foundation have always been part of the major stakes since the 16 th century. She came in Mängəśto before 1559, during the reign of Gälawdewos. Even if we did not find any exact dating of the construction in the official chronicles, we can still think that she built a church. Indeed, we do not find any mention of a pre-existent foundation. Thus she would have begun her project in parallel of her son's foundations, increasing the royal control on the other side of Abbay River. If

we cannot conclude on the exact background of this queen, according to the chronicles of the 16 th century, we remark that she was involved in a significant union of the royalty with the kingdom of Səmen, as her mother was married to Gedewon, the ruler of the Falaša. She might also have family ties with some Goğğam ruler as the region cannot be considered as integrated in the royal kingdom in the beginning of the 16 th century.

Nevertheless she chose East-Goğğam for her royal foundation. She was following a policy begun by her predecessors which was probably quickened by the fear felt at the arrival of Oromo people in the region. After she died, in 1568, the kings keep on increasing their physical presence in Goğğam. They stayed in different royal residences that they built in the area: for example in Säbrad located at the south of Lake Ṭana, in Q w arab located next to Moṭa and in Sarka. Susneyos received from his father, the queen's grand-son, some lands in this area. East-Goğğam became a place of royal interest and appeared much more in the official chronicles 124

. Mängəśtä Sämayat was a strong local base for the royalty during her lifetime. It was not the only political center of the 16 th century, but it was the place where the successions were played, attesting of the great influence of this queen in the political game. However, considering that it was the residence of the Queen, a main character of the 16 th century's royalty, we cannot ignore its effective influence and the importance of this province in Ethiopian History. She had been behind the scenes of every reign when she was alive and imposed herself as the "Key-Queen" of the 16 th century.

But apparently the church did not succeed to maintain its part in the geopolitical map of Goğğam considering the silence about this place during two centuries. The documents found in the church attest that it was destroyed by the Oromo during the reign of Iyasu and never rebuilt before neguś Täklä Haymanot 125 . Säblä Wängel supported the Ewosṭatewos' movement, following the steps of Queen Ǝleni in Goğğam.

The priests became important in the later lists of teachers of the qebat's school. 3 The Oromo people are called pejoratively in the Christian texts "under the name of "Galla". E. Fiquet by studying the structure of the Oromo society points in his analyzes the fact that the Oromo were not all nomad pastors. Their tribal system based on the Gadaa reinforced the spirit of conquest and combined to the idea of exogamic marriage marginalized a certain part of their population and specially the cadet sons. This part of the population was then expelled on the boarder of their territory in dry lands and then they were obliged to practice pastoral activities. In the 16 th century this branch of the Oromo population was in lack of space. So after the attacks ruled by Grañ who disorganized the Christian kingdom, they had the opportunity to come and settled there, expanding by this way the Oromo territories, and finding there a better way of life There it seems that the copyist is not the same. He comes again on the history of the settlement but focuses more on the administration of Go• • am. From folio 13r to folio 15v historical events of the 19 th century are described: the battle of Žmbabo, the history of the conflict between Menelik and Täklä Haymanot, the campaign against the Mahdist, the campaign of Yo% annes IV in Go 15 He uses historical books on Ethiopian History as the Mächäfä Giyorgis Wäldä Amid (f. 1 v/ n°279, f. 3 r/ n°276, f. 7v/n°267 ),ÄbushäkYr Mächäfä (f. 7v/n°267 ) and ), a book written by a certain Dane'el (f.4 r/n°274, f. 8r/ n°266). He also makes some reference to religious works like the Mächäfä Qelementos (f. 1 v/ n°279), the SYnksar (f.4 r/n°274), Zena ŽskYndYr(f.4 r/n°274), Tä'ämrä Iyasus(f.4 r/n°274).

16 Aristotle (f. 1r /n°280) and a certain Sofonias (f.3v/ n°275; f.4 r/n°274) are the historical reference for the history of the kingdom in Ancient Time. Later, the author, talking about the Nile, says he found some proofs in a French book called "Larus" (Larousse) (f. 3 r/ n°276). 17 We will present briefly the work of Aläqa Täklä Iyasus in this study. But a deeper analyze has to be made. 18 The text of Aläqa Täklä Iyasus is currently known as the History of Go• • am: we had to find a different name for this manuscript. 19 The book is tall by its size. We may then think that it has been copied in the church as it would not have been easy to carry on a journey. In case of emergency, it is also easier to take away some folios with the most important histories than a tall and heavy book. It might also be the opposite; the clergy could also have copied the main events on separate folios, maybe more useful for the different ceremonies of the year. 20 Like the Chronicles of the zämänä mäsafYnt translated by Well Blundell, 1989, in The royal chronicle of Abyssinia 1769-1840, Osnabrück, 543 p. 21 Folios f. 1r to f.2v are blank. Then from f. 3r to f. 4v we have a list starting from Adam to Noah. It continues and ends with the last biblical Kings. On folio 5r we find the genealogy of Mary and Jesus. Then folios f.5v to 15r are the narrative of King Constantin, and all the genealogy until AbrYha and AcbY% a is given. Folio 10v is related to Yared. From folio 15v to 20v, it is the story of Queen Azeb, Solomon and their son Žbnä $ äkim. On folios 21r to 22r, we find the genealogy of the kings after Queen Makeda until the coming of Christianity in Ethiopia during AbrYha and AcbY% a's reign. The genealogy continues from folio 22v to folio 24v and presents the coming of the 9 saints (f. 22v), Kaleb, Del Na'ad and the Zagwé dynasty. Folios 25r to 30r are dedicated to the change of dynasty focusing on the arrival of YYkunno Amlak and Saint Täklä Haymanot. Then the genealogy goes on with his royal descendants f. 30v to 34r with special interest on Saint Ewosm atewos, and then with the kings Amdä beyon and Sayfa Är'ad. The next folios (f. 35r to 40v) give long development on Dawit II and the coming of the True Cross in Ethiopia. Folio 41r is related to Zär'ä Yä'Yqob and his son Bä'Ydä Maryam, the folios 41v and 42r to Eskender, Amdä beyon, Na'od, and LYbnä DYngYl. The history of the campaign led by LYbnä DYngYl against Grañ and the coming of the Portuguese is the main interest. Nothing is said on his wife, not even her name. Folios 42v to 45r are related to the reign of Gälawdewos, his military successes, the building of two churches (Tädbabä Maryam and Mäkänä Sämä'Yt) and the religious debates that happened during his reign. Then, folios 45v to 46v deal with the reign of Minas and the conflict he had with his mother Säblä Wängel. It continues with the reign of Zärcä DYngYl and his wife Maryam Sena(f. 46r to 49v).There is a little digression on the history of different monks in Ethiopia since the time of Lalibella. (f.50r-51v).The text goes on with the reign of Ya'Yqob, Zä-DYngYl, SusYnyos (f. 52r-53v). At folio 54v the genealogy stops and starts again from the Biblical Kings. On folio 59v, the genealogy comes back to the reigns of Zärcä DYngYl, Zä-DYngYl and SusYnyos, but goes this time further until the death of this one (f.65v). Then it continues with the reign of Fasilädäs (until f. 68r), Yo% ännes I (f. 68rv) and Iyasu I (69r). Nothing is said on his son Täklä Haymanot, and brief notices are found on Tewoflos, Yosm os, Dawit, and Bäkaffa (f. 69v-70r). It is followed by the history dedicated to the reigns of Iyasu II and Iyo'as until the zämänä mäsafYnt (f. 73r). Then the handwriting seems to change, but it gives long development on ras Mika'el during the reign of Iyo'as.(f. 74r to 77r). It continues with the reign of Täklä Giyorgis and of different famous lords (f. 77v-84r) until the reign of Yo% ännes IV. On folio 84r-v, there is a genealogy of abuna starting from abba Salama (Frumence). The handwriting changes here again. It goes on with another genealogy starting from Arwe -what has already been seen on folio 59r-followed by Queen Azeb and Žbnä $ äkim, and ending with the Zagwe (f. 85v-.87r). It is followed by brief notes on the kings from YYkunno Amlak to Yo% ännes IV (f. 87v-95v). 22 This tradition explains the end of the reign of Minas who wanted to dismiss his mother. Minas wanted to crown Žtege his wife SYlus * ayla, while his mother was still alive. Säblä Wängel was supported by two monks called ZYkre and Pawli who stood up for her and excommunicated the king. Minas imprisoned them. Pawli died. After a time, Minas regretted and took ZYkre out of jail. The monk revenged and used trickery. Following the subterfuge of the monk, the king forced all the monks to strip off their clothes. Seven days after that, the king died. This tradition would deserve a further study. 23



  define the role of this royal foundation during the time of Säblä Wängel, and understand what parts it played in the religious context and in the politics of the royalty during the 16 th century. The sources in our possession: The manuscripts of the church and the work of Aläqa Täklä Iyasus For this research, two different topics are interrelated, Queen Säblä Wängel and the Church of Mängəśto. To fulfill this study, we organized two fieldworks in the region of East-Goğğam and especially in Mängəśto, in order to follow the footsteps of this queen, her settlement in the area and the foundation of this church. We found some manuscripts in the Church of Mängəśtä Sämayat in 2008 8 , and we have completed this fieldwork by collecting oral traditions in 2009 in the province of East-Goğğam 9 . The clergy of Mängəśto has in its possession different manuscripts which are copies from the end of the 19 th and the beginning of the 20 th century. These documents are not yet recorded by the official authorities and would deserve a publication by their own. Some of them perpetuate the memory of Queen Säblä Wängel as the first founder of the church, especially two Tarikä Nägäśt (History of Kings). o Tarikä Nägäśt or History of Mängəśto The first manuscript is called Tarikä Nägäśt by the clergy of Mängəśto. It is a late copy of a text produced at the beginning of the 20 th century 10 . It ends with the narrative of the death of neguś Täklä Haymanot, King of Goğğam in 1901 11 . The manuscript is large. It measures 47 cm high by 42 cm large. It is written in blue and red ink, partly in Amharic, with some ancient forms taken from the Ge'ez. There are 31 pages numbered decreasingly from 280 to 251. There is no illustration or drawing. The text is different from the one of the Abbreviated Chronicles also called Tarikä Nägäśt produced before 12 .

59 :

 59 of the time when it is said to have been edified. The late documents date the construction of Mängəśtä Sämayat during Ləbnä Dəngəl's reign. That is why our investigation will start from his chronicle. Mängəśtä Sämayat (Herman Margaux June 2008) o o o A challenged dating in the light of the sources of the 16 th century The Chronicle of Ləbnä Dəngəl keeps quiet on that subject: the queen is not directly mentioned and her name not even quoted. The text is mainly based on Grañ's invasion. But as there is no record on the first years of the reign of Ləbnä Dəngəl 58 , we could have imagined that Säblä Wängel built the church before the conflict with Imam Grañ Ahmed began to be too intense, prior to 1527. But at that time, two powerful queens were at the court as regent Queen Ǝleni, Bä'ədä Maryam's wife, known to have built Märṭulä Maryam located in the district of Ǝnnabse, and Na'od Mogasa, Ləbnä Simplified Genealogy of the royal family of the 16 th century mother, who made a foundation in Getesemäni in the district of Ǝnnase 60 These

90 .different realities 91 .

 9091 But in opposition to the idea advanced by Tadesse Tamrat, he states that it was not a convincing proof of its integration. Goğğam was still ruled by its own nagaš, a title which implies Then, following the different roads used by the kings of the 16 th century, D. Toubkis remarks that the Goğğam under their influence is just represented by the oriental part of the actual region, which follows the flows of the Nile.

95 .

 95 Na'od Mogasa, the mother of the king chose the place of Getesemani in Ǝnnässe 96 to build her foundation. The interest showed by these queens is a proof of the attraction of the region and of the strategy of physical implication of the royalty in the oriental part of Goğğam in the first decades of the 16 th century. In the 28 th year of Ləbnä Dəngəl's reign, Grañ reached this region and destroyed Märṭulä Maryam

97

 97

Figure 1 :

 1 Figure 1: Sablä Wängel and East-Goğğam in the 16th century

  she have less influence than before? But at that moment, she kept the crown with her 118 . The fact that she had in her possession the attributes of the royalty shows her main status in the hierarchy of the officials of the royalty. She finally succeeds to maintain the young Śärṣä Dəngəl in his sovereignty119 and thus to keep her rank of regent until she died in 1968 120 .

  Täklä Haymanot and to Goğğam 14 . It is an ethnographic and geographical History of Goğğam. It covers the period of Ancient Ethiopia, from the time of Creation until the Tarikä Nägäśt of Mängəśto is not expressed in the same way as it is in René Basset's work 23 . In the other Abbreviated Chronicles and complements given by modern historians, only few mentioned this account 24 . Nevertheless, we found it in a tradition collected by A. Tarikä Nägäśt. The end of the reign of Täklä Giyorgis, before Yoḥannəs IV ascends the throne in 1872 is for now the terminus post-quem for the date of writing, which is different from the date of the copy.

	d'Abbadie then published by C. Conti Rossini in 1899	25 . I. Guidi published some
	complements in 1926, and added to the corpus of Abbreviated Chronicles two different
	manuscripts	26 : one mäṣḥäfä Kəbrä Nägäśt undated and another manuscript from Gondär
	written in Amharic in 1900. The quarrel is described (folios 28r 11)	27 . It is also mentioned
	in the History of Goğğam written by Aläqa Täklä Iyasus (ch. 16 p. 41-42) translated in
	English by R. Cowley in 1989	28 . A structural and textual study of these texts will highlight
	the dating of this
			21 .
	Focusing on the reign of Gälawdewos and Minas, the Tarikä Nägäśt of Mängəśto describes
	a quarrel (folios 45v to 46v)

death of neguś Täklä Haymanot of Goğğam and Käffa in 1901. We do not know the author as there is no colophon. But the author has a deep knowledge of the Ethiopian literature

15

and even quotes foreign sources that have been consulted to write this history

16

. The information given by the text of this manuscript show some close similarities with the work of Aläqa Täklä Iyasus 17 . A deeper investigation is needed. We will call it History of Mängəśto for practical reasons of understanding and writing

18

. Next to this book, we found on separated vellum folios some extracts of it written with black ink, as if it had been copied first on separate folios and then copied in the church in one book 19 . o Tarikä Nägäśt The second Tarikä Nägäśt is smaller. It measures 15cm square and is composed of 97 folios unnumbered. It is written in a manuscript on vellum in black ink. The author is unknown. It seems to have been written in the second part of the 19 th century: Yoḥännes IV (1872-1889) is the last King referenced, and nothing is said about King Menelik II or King Täklä Haymanot, neguś of Goğğam and Käffa 20 . It is not a regional history. It is less centered on Goğğam. The structure of the text looks much more like a Tarikä Nägäśt, than the one introduced before: it follows the traditional list of kings with brief notes on their history and the notes have a different content from the History of Mängəśto's 22 that happened between the King Minas and his wife, Səlus Ḫayla, on one side, and his mother Säblä Wängel and the clergy of Mängəśto on the other. This tradition is an example of the particularity of this chronicle. Most of the time, we do not find it in all the different well-known Tarikä Nägäśt. It is not recorded in the Chronicles translated by R. Basset. We can also note that the history given for each king in the o A Nägärä Maryam and separate folios:

 The contemporary sources of the life of Queen Säblä Wängel : the Official Chronicles of the 16 th century

  But one informant of Mängəśto, Təzäzu Gälayä, gives us one interesting account: "The main text of the Glory of Kings had been taken by äṣé Yoḥannes, the The History of Goğğam and the Genealogy (Zena) of its rulers by Aläqa Täklä

	century's chronicles, Manfred Kropp shows that some manuscripts preserved some o Iyasus "traces" of the original version 43 . He made a lot of essays on this subject, trying to find
	the author(s) and to analyze how this compilation had been built 44 . He finally concluded
	Next to these materials, another text has to be taken into account. It is Aläqa that after a last censure of King Susənyos, they have been compiled in one book between
	Taklä Iyasus Waqjira's History. Originally called Nägäro Waqjira, Täklä Iyäsus was born in 1616 and 1622 and then copied in that form later on 45 . At the time of this reconstruction,
	1875-76 in Gend Bärät. He was brought to Goğğam in June 1878 and baptized Täklä Iyäsus the chronicles of Ləbnä Dəngəl, Gäläwdewos and Minas are compiled to be an 33 . He grew up being as an attendant in the däğğazmač Yälämtu Gošu's family, one introduction to the official Chronicle of Śärṣä Dəngəl that is censured by Susənyos 46 . The
	of the uncles of Täklä Haymanot. He studied to be a painter in Dima Giyorgis, a famous monastery in Ǝnnämay, under the supervision of a certain abba Sahəlu chronicle of Śärṣä Dəngəl has been translated by C. Conti Rossini in 1907 47 and M. Kropp 34 . He was actively translated and published the three previous chronicles in 1988 48 . King Ləbnä Dəngəl and
	involved in the painting of churches and other artistic works from the late 1880s' to the King Minas did not have, apparently, their own official chronicle, except in the texts of the
	1920s'. He died in Däbrä Marqos before the Italian occupation. What seems to be a copy of this manuscript is found in the National Library compiled with other materials introduction of Śärṣä Dəngəl's reign. But we know that for King Gäläwdewos a text 35 . In 1906-07, he started to write a History of Goğğam written after his death is frequently assimilated by historians as his official chronicle 49 . In 36 and also a genealogy of the people of fact, it is much more a hagiography where King Gäläwdewos reproduces finally the life of
	the region. The genealogical text is copied and subsequently incorporated in register at the national Library under the title of "የዘመን፡ ታሪከ፡ ማጠራቀሚያ።" 37 . The original of this the homonym Saint Martyr 50 .
	manuscript is kept in the hands of ato Wudu Fänta who lives in Däbrä Marqos town	38 . The
	main purpose of this text is to trace the genealogy of the first ancestors who settled in
	Goğğam for each district. More specifically it aims at listing the lineage of the family of
	nəguś Täklä Häymanot. Its structure and its narrative shows at least close similarities
	with the text of the History of Mängəśto	39 , but a deeper textual analyze has to be done.
	Using the genealogy produced by this historian from Goğğam, Tadesse Tamrat concluded,
	regarding our matter, that "Mangesta Samayat became virtually the center of the
	Kingdom in the 16 th century"	40 .
	Unfortunately, none of the manuscripts found in Mängəśto seems to have been
	written during the 16	th century when Säblä Wängel was alive. It is then fundamental to
	analyze the official sources of her time, and the context of their writing.
	We will focus our concern on the official chronicles of Ləbnä Dəngəl, Gäläwdewos,
	Minas and Śärṣä Dəngəl, kings of the 16 th century. Generally produced at the royal court,
	official chronicles were controlled by the sovereigns. Nevertheless the censorship appears
	present text is a copy" to be a trait shared by the Ethiopian historiography and the collective memory 31 .	41 . Thus
	the chronicles of the Ethiopian kings under their royal control tell about events that fix Thus, the clergy of the church does not have any preserved manuscript of the 16 th the official view, which is to be taken into account by historians who want to use them as century in its possession. King Täklä Haymanot, neguś of Goğğam and Käffa rebuilt the church in 1887 (1880 AM) which has been destroyed a century before 32 historical sources. The official chronicles dedicated to the kings are found since the end of , a time when it the 18 th century bound together in one manuscript which in fact is a compilation built by could have lost its original writings. the däğğazmač Ḫaylu 42 . Focusing his attention on the manuscript tradition of this 16 th

 The

settlement of a queen in Mängəśto:

	Here starts the discussion. We will compare the late statements, related to Säblä
	Wängel and her foundation, found in the sources produced after her death and in the
	local traditions of East-Goğğam to the contemporary accounts found in the sources of the
	16 th century.

 Dating

the foundation of the church:

  What is the dating given by the sources of the church? In the Tarikä Nägäśt of the church at folio 45v, a quarrel is recorded between King Minas and his wife Səlus Ḫayla on one side, his mother Säblä Wängel and the clergy of Mängəśto on the other side

	Wängel". Thus Säblä Wängel is remembered as the first founder	53 of Mängəśtä
	Sämayat	54 .
			o During Ləbnä Dəngəl's reign?
		Documents and oral traditions, which have been collected during the different
	fieldworks, keep for the first building of this church the memory of the royal ordinance of
	Queen Ǝtege Säblä Wängel, Ləbnä Dəngəl's consort (1508-1540). They call Säblä Wängel
	to be the first founder of the church. For example, a recent document found in the
	separate folios of the church seems to be the last history of the foundation of the
	church	51 . This is a memorial text written at the occasion of the death of the princess
	Säblä Wängel, the grand-daughter of King Täklä Haymanot in 1969. We find this
	account:"She loved Our Lady Mary deeper in her heart and due to this, she built a
	wonderful church in her name called Mängəśtä Sämayat, the country of Säblä Wängel the
	first, the wife of Ləbnä Dəngəl, King of Ethiopia."	52 . Another mention, written in 1887
	when the church was rebuilt by nəguś Täklä Haymanot of Goğğam, supports this idea: "It
	[Mängəśtä Sämayat] had been built for the first time on the will of our queen Säblä

55

.

In

this occasion, it is reported that "[…] Säblä Wängel, built during her husband Ləbnä Dəngəl's reign, the beautiful church called Mängəśtä Sämayat" 56 . The author of the History of Mängəśto gives a different version. : "its name is Mängəśtä Sämayat and it is the Kingdom of Heaven. That's why King Ləbnä Dəngəl and Queen Säblä Wängel celebrate this church 57

  Until now, I didn't find any earlier evidence. To conclude, we cannot date the construction of the foundation, and we don't know if Säblä Wängel created it or if she developed an already existing church that would then have said to be built by her. The queen was living in Mängəśto at least during the time of Śärṣä Dəngəl and the reign of Minas, and probably before. It seems to be difficult for a queen to have made the project of a royal church foundation during the last part of the Ləbnä Dəngəl's reign and at the beginning of her son's: the war was raging. Thus Säblä Wängel might have begun this project during the return of a certain stability in the country, probably in parallel ofGälawdewos's foundations (Tädbabä Maryam and Mäkana Säma'ət).The Ethiopian historiography remembers the reign of Ləbnä Dəngəl as being the time of the construction of the foundation. It keeps in mind that Säblä Wängel was his consort and that she founded Mängəśtä Sämayat. As there is not any exact dating of the construction in the official chronicles, historiographers replace it naturally during the reign of her famous husband, with whom she is always associated concept that did not exist in the 16 th century. But cannot it be a way to say that Säblä Wängel comes from Goğğam, but from a non-Amḥara part of the population? Describing the genealogy of the Šime families, he introduces thenƎmašənkor, who married to Ḥəzba Askər, gave birth to Fətḥ, Rət', Mär'ata Bägg'u and Amättä Bägg'u. Fətḥ got married to the Baḥər Nägaši Tewodros, the ruler of Tigray. They got two children: Säblä Wängel and Ǝnqopazyon 72 . Aläqa Täklä Iyasu states that her father comes from Tigray. Säblä Wängel would then be the direct result of a political alliance between Goğğam and Tigray. And about the Šəme, this historian says that they are one of the people who settled in East-Goğğam during the Zagwe73. So, it is a way to suggest that her family has set in Goğğam a long time ago and before she became queen.By marrying Ǝmašənkor to Ḥəzba Askər it is a polical alliance between the moving Šəme and the local Ğara Šum's family that is described by Aläqa Täklä Iyasu.

	During the 20 th , Aläqa Täklä Iyasus is more precise in his genealogy. He presents
	Säblä Wängel to be the descendant of Ğara Šum

67

. We can wonder if this was the result of a lack of knowledge or a conscious act of the chroniclers.

 The Choice of East-Goggam: Why did Säblä Wängel come and settle in

Mängəśto?

Following the same method as used for the dating of the construction of Mängəśtä Sämayat, we will focus ourselves on what the sources that were produced after her death say about her origin and the reasons that could have influenced her to settle there. Then we will compare the statements drawn to the records of the 16 th century.

o Does the queen come from Goğğam? A late attribution? All the documents produced since the 18 th century attributes to her a Goğğam's background. The chronicler of the reign of Iyasu II and Mentewwab 68 , beginning his work with the genealogy of the king and his mother, says on this occasion that: "Son père [of Ləbnä Dəngəl, who is Na'od] le maria à une femme du Goğğam, qui s'appelait Ǝtege Säblä Wängel

69

." That can mean that she lives in Goğğam or that she comes from there. But that can also be the result in the 18 th century of a whole life dedicated to this region: because she took root with success in Mängəśto she is remembered as a woman from Goğğam.

[START_REF]um is the name of $ Yzba 'ÄskYr who is sometimes called Tarbinos[END_REF]

and gives him the title of Ǝnnämay balabat

[START_REF] Täklä Iyasus | [END_REF]

. Because Ğara Šum is nowadays known as a place in Goğğam, it is easy for the contemporary readers to think that she comes from Goğğam. And if we read between the lines, the word balabat refers to a non-Amḥara population. Aläqa Täklä Iyasu uses here again a modern

  Yodit was a relative of Queen Säblä Wängel. But he describes her not as the step-mother of King Gälawdewos but as her step-sister[START_REF] Basset | ወተፄወዉ፡ ጌዴዎን፡ ወዮዲት፡ ንጉሥ፡ ንጉሥ፤ ምስሌሆሙ፡ ወንዋይኒ፡ ጠፍአ፡ ዛልቦ፡ ኊልቊ፡ ወበውእቱ፡ ዘመን፡ ተናፈቀ፡ ሕዝበ፡ ኢትዮጰያ፡ በእንተ፡ ፋሲካ፡ እምብዝኃ፡[END_REF] . Both translators chose a different meaning for the Ge'ez word "ḥämat". This word comes from the ge'ez "ḥmw" and according to W. Leslau's dictionary[START_REF] Leslau | Comparative dictionary of Ge'ez[END_REF] it can be as well step-mother or step-sister. We might agree with the translation of M. Kropp. René Basset adds in a note that Gedewon was the ruler of the Falaša of Səmen 79 . Nevertheless we can wonder if Gedewon is the father of Säblä Wängel. I personally think that he is not and that Gedewon may have been the second husband of Yodit. If he has been the true father of Säblä Wängel, when this couple got rapt by Muslims, the chronicler would have say that they were both the step-father and the step-mother of the King. Thus two questions stay unanswered. We don't know neither the native place of her mother, Yodit, (a name that was given to her when she marries Gedewon), nor the name of her father.Who is Yodit? Gälawdewos on his way to Səmen is said to have been welcomed by the Agaw from Ləware, from Hotsa and from Ṣälämt 80 . With this add, R. Basset notes that Gälawdewos is related through his mother's side to the Agaw of Lasta

Kropp gives one interesting detail: her mother's name is Yodit, Gedewon's wife. In 1539, these two persons (from the nobility) have been rapt by Grañ Ahmed 76 . In the manuscript translated by R. Basset, it is marked that 81 .

one main political center during the second part of the 16 th century

  église Mängəśtä Sämayat (Royaume des cieux). C'est par les fils spirituels de ceux-là que furent instruits dans l'interprétation des livres saints abba Täṭämqä Mädḫən, du couvent de Gäšola, Gažəge et Wägäda; abba Yoḥännes de Däbrä Ṣelalo, abba Ṣewa Dəngəl, abbé de Däbrä Gonğ. Ce sont eux tous In this spiritual line of thoughts, Zəkre and Päwli are presented to be two monks from Mängəśtä Sämayat 100 who played a main role in the preaching and the spreading of this belief. R. Cowley, working on Zəkre and Päwli, introduces them like commentators of the Bible and he concludes his analysis saying that their main activity is dated to the reign of Gälawdewos reference in the church's preaching of this movement. For almost a century, it is still surprising not to find any mention of these preachers or of the church. In Mängəśto and in Qoga, they are said to come from Däbrä Ṣemuna 107 also associated to Säblä Wängel.Susneyos is said to have plunder her possessions in Däbrä ṢemunaWe can thus conclude that Mängəśto was one of the religious center supporting the Ewosṭatwos' movement in East-Goğğam. Its clergy represented by Zəkre and Pawli turned their activities in the commentaries of the Bible and were apparently religious teachers. Their teachings seem to have been spread amongst the inhabitants of Goğğam. , we cannot deny the importance of the foundation in regards of this extreme association made between Mängəśtä Sämayat and the royal sphere. But to go further, we can see that in the beginning of his reign, in 1559, Minas and his mother Säblä Wängel were in Goğğam. It is said that Minas came to Mängəśtä Sämayat where he met his mother, and from where he moved with her. But "angetreten" is prior to "brach auf". That can give us two solutions. The first is that Mängəśto was his royal residence and he had to move from it with his mother who will never separate from him. The second is that on his way, Minas had to come to Mängəśto to receive his power, having his sovereignty confirmed by his mother.

	116
		108 . We can thus think
	qui enseignèrent cette foi orthodoxe aux habitants du Goğğam et du as we still find some mention of this church in the two centuries coming that it
	Q w ara. » superseded Mängəśtä Sämäyat 99	109 . An investigation on this church might bring some
	more details.
	Mentəwwab and her son were thus presented as followers of Ewosṭatewos and
	Walatta Petros, a saint woman who developed her activities in the region of Laka Ṭana in
	the 17 th century. Following the hypothesis of	D. Toubkis stating that Queen Ǝleni had family ties with
	the local rulers of Goğğam, he placed Ǝleni as representing the Goğğam's position when
	she joined her foundation to Ewosṭatewos. He interprets it as a way to counterbalance the
	central authority and to mark its independency because usually the kings were
	foi participent les gens du Goğğam et ceux de Q supporting and were supported by the church of Däbrä Libanos w ara, car ils avaient 106 . After her death and the destruction of the church, Säblä Wängel could have chosen, in the light of these late été instruits par les fils spirituels de l'abuna Ewosṭatewos, à savoir le rə'sä mentions, to follow this movement to recreate the main Ewosṭatewos' center in East-rə'usan Täklä Maryam de Däbrä Ǝleni ou Märṭulä Maryam, et äbba Särṣä Dəngəl, abbé de Däbrä Sarat; descendu en Egypte pour y apprendre les Livres Goğğam that had burnt before.

de l'Ancien et du nouveau testament en 7 langues, il retourna en Ethiopie et enseigna en langue ge'ez, et 'Ämdä Ḥäwaryat qui composa le Mälkə'ä Iyäsus ; leur pays était Tädbabä Maryam. Il instruisit abba Zəkre et abba Päwli, prêtres de l'101 . A mention found in Gälawdewos's Chronicle shows Zəkre announcing to the Queen the death of this king, her son, which event led to the coronation of Minas 102 . The Abbreviated Chronicle's tradition records that Zəkre and Päwli have been in opposition to King Gälawdewos about the Portuguese's faith (Catholicism), that the King is accused to love 103 . Another late tradition shows these two priests on the side of Queen Säblä Wängel in argue with Minas 104 .These elements attest that Zəkre is a member of the religious community but that he is also close to the royal sphere, often in opposition with the reigning kings and supporting Säblä Wängel. Unfortunately, except for the presence of Zəkre at the court of Gälawdewos, none of these statements are found in the texts produced when Säblä Wängel was alive. But what is interesting to note here is that in the beginning of this century, two royal foundation supporting two different religious movements have been built: Märṭulä Maryam joined to Ewosṭatewos and Getesemani to Däbrä Libanos 105 . It attests of the interest of both royal and religious power to be represented physically in East-Goğğam.

But they were apparently famous teachers of the Ewosṭatewos movement and their activities were important enough in the memory to appear in the genealogy of a royal foundation more than a century after they passed away. They became with time a  Mängəśto, As we state previously, Minas was in Mängəśto at the beginning of his reign 110 . A textual analysis of this account has to be done to get a better historical point of view on its function at that time. ወአምድኅረዝ ፡ ተንሥአ ፡ ዝንቱ ፡ ንጉሥ ፡ እምመግሥተ ፡ ሰማያት ፡ ዘይእቲ ፡ መካነ ፡ መንግሥስቱ። እስመ ፡ ሀልዎቶሙ ፡ አሜሃ ፡ ኮነ፡ በምድረ፡ ጐዣም ። ወእሙሂ ፡ ንግሥት ፡ ሖረት፡ ምስሌሆሙ ፡ ወኢተፈልጠት ፡ እምኔሁ፤ ታስተጻንዕ ፡ ሎቱ ፡ ሕገ ፡ መንግሥት። 111 Manfred Kropp, translating his chronicle, interprets "ዘይእቲ፡ መካነ ፡መንግሥስቱ" 112 as "dem Orte, wo er die Herrschaft angetreten". Does it mean that the king have to come to Mängəśto to see his power recognized? Does Minas receive his crown there? Was it the place from where he organized his actions? For D. Toubkis, we have to see Mängəśto as "his royal residence" 113 . Literally it means "in the place of his kingdom" 114 . Whichever meaning we chooseMängəśtä Sämayat is another time called "መካነ" after the death of Minas, when his son Śärṣä Dəngəl was chosen to ascend the throne 115 . Śärṣä Dəngəl was faced to an opposition that brought him to reach the "place of his grand-mother Säblä Wängəl, Mängəśtä Sämayat"

  The tradition attributed to Mängəśtä Sämayat to be involved in the development of the School of qebat (Unction) which had strong influence in Goğğam. Däbrä Ṣemuna, another Ewosṭatian church connected to Säblä Wängel may have superseded Mängəśtä Sämayat in its religious duty 126 . Nevertheless to go further on this point, some more historical researches have to be done on this movement and its birth 127 . The qebat did not exist before 1620 as an independent school of thoughts 128 . It is then difficult to go further on. If Säblä Wängel was supporting a school of thoughts which have been then condemned, the silence in the official sources is not surprising. The link with this movement and its potential role in the theological debates is probably the reason of its decline in the official sources until the end of the 19 th century. At this moment, Säblä Wängel and her foundation of Mängəśtä Sämayat became essential in the histories produced in Goğğam as it is proved by the texts of the manuscripts of Mängəśta Sämäyat and by the works of Aläqa Täklä Iyasus. The Covenant of Mercy is a Pact made between Mary, Jesus and God. The Christian community can intercede directly with God by praising Mary. (voir C. Bosc-Tiesse, "How Beautiful She Is!" in Her Mirror: Polysemic Images and Reflections of Power of an Eighteenth-Century Ethiopia Queen", Journal of Early Modern History, Brill, v.8, 3-4, p. 300-318 2 See the map, from the Ethiopian Map Agency, records under the n° 1038 A3.

1

  We did not find any record speaking about the exact date of their union, but they give birth to four sons: Fiqm or, Minas, Yä'Yqob, and Gälawdewos. Gälawdewos mounted to throne in 1540 at the age of 18. Thus he was born in 1522. The birthdates are not recorded in LYbnä DYngYl's chronicle,but according to Asma Giyorgis, Gälawdewos was the youngest son. Asma Giyorgis (in Bairu Tafla, 1987, Asma Giyorgis and His Work: History of the Galla and the Kingdom of Šawa, Stuttgart, p.151) We can conclude that at least the wedding must have happen before 1518. (And we don't count here the daughters!)5 Basset, 1882, p. 117 : « La cinquième année, le roi fit la guerre au bâchâ ; alors mourut Ité Säblä-Ouengèl, mère du roi. » around 1568 but in the Chronicle of Zärcä DYngYl tells (Conti Rossini C., 1907, Historia regis Sarsa Dengel (Malak Sägäd). C.S.C.O. 20, Paris, p. 103) also that in 1579, « ce jour, qui était le 2 du mois de hédar, c-a-d de kanum 1er, fut le jour de la mort de la Grande reine Säblä Wängel , qui aimait le jeûne et la prière, craignant le Seigneur et aimant les hommes, que le Seigneur reçoive son âme dans le royaume des cieux avec les âmes de ceux qu'il fait grandir dans la religion. ». Both texts don't give the same date. We might believe the Chronicle of Zärcä DYngYl as is it has been written more contemporarily than the Abbreviated Chronicles who start to be written in the 18 th century. But it might also appear that the mention found in the long chronicle is just to remember the day of her death, like a memorial "tazkar", 10 years after the official date. We found another mention in the text related to the campaigns of Zärcä DYngYl against the Falaša translated by J. Halevy in 1907 in the Bulletin of Geographie gives the day of the 25 H•dar, the 1 st kanoun for the death of Säblä Wängel.(p. 129).6 He shows the ability of the narrative to describe MängY[to as the center of the kingdom by linking it to King Efrem who is said to have settled there at the center of Go• • am on his way back from Jerusalem with Menelik I. Tadesse Tamrat thus shows an interesting example of historical reconstruction. 7 Taddesse Tamrat, 1994, "Ethiopia in Miniature: The Peopling of Gojjam", New Trends in Ethiopian Studies, Proceedings of the Twelfth International Conference of Ethiopian Studies, Michigan State University,v.1, p. 959.8 We have visited this church on 20 Genbot 2000 with Habtamu Mengiste, a Ph.D. Candidate from the University of Illinois at Urbana-Champaign. We found the church in restoration. One year after, it was not yet finished.9 It is frequent that the literate clergymen in charge of the history of the Christian community found their knowledge not in their own manuscripts but from recent published booked written in Amharic as the one of Täklä bädYq Mäk w Yriya (1958-59) who used the work of Aläqa Täklä Iyasus (Täklä Sadéq Mäk w ériya, 1958/59 A.D, (የኢትዮያ፡ታሪክ፡ከአጼ፡ልብነ፡ድንግል፡እስከ፡አጼ፡ቴዎድሮስ።, ('History of Ethiopia: From ase Lébnä Déngél to ase Tewodros), Addis Abäba; and also as the work of Ädmasu Jambare printed in 1954 in Addis Ababa(መጹሎተ፡አሚን፡የሃማኖት፡ሚዛን፡ከመልአከ፡ብርሃን፡ አድማሱ፡ጃንበሬ፡ትዘጋጀ።, 1954, Addis Ababa.) But strangely, they do not seem to know that Aläqa Täklä Iyasus was from the area.10 The documents has a seal but it is unfortunately illegible. 11 When Yo% ännes IV assumed the throne in 1872, he created four administrative units: Go• • am and Käffa, BägämdYr and SYmen, Shewa and its dependencies and Tigray and its dependencies in the north. Täklä Haymanot (I870-190I), ras of Go• • am under the name of ras Ädal Tessema , received the title of negu[ of Go• • am and Käffa in 1881, at the same time Menelik II received the Shoa.( Getatchew Haile, 1986, « The Unity and Territorial Integrity of Ethiopia », The Journal of Modern African Studies, Cambridge University Press., Vol. 24, No. 3, p. 465-487) 12 The writing of Abbreviated Chronicle began in the 18 th century and have been definitely fixed in the monastic circles after Bäkaffa's death in 1730. (C. Bosc-Tiesse, 2008, Les Iles de la mémoire, Fabrique des images et écriture de l'histoire dans les églises du lac l ana, XVIIe-XVIIIe siècle, Paris, p. 19 and ch.VI ; A. Caquot, 1957« Les «Chroniques abrégées» d'Éthiopie », A.E, p. 187-192, and especially the works of M. Kropp, 1983-84 ,« Réédition des chroniques éthiopiennes : perspectives et premiers résultats », Abbay, 12, Paris, p. 49-72)13 The first four folios define the history of Ancient Ethiopia as the blessed country chosen by God. The Nile compared to the biblical river Gyon is one vector of this narrative, and all its tributaries are given. At folio 4v the author begins to focus on Go• • am with the construction of churches made by AbrYha and AcbY% a (two mythic kings: to get more information on these kings see the paper of B. Hirsch and F.X. Fauvelle-Aymar (in, 2001 « Aksum après Aksum. Royauté, archéologie et herméneutique chrétienne de Ménélik II (1865-1913) à Zära Yaqob (r. 1434-1468) », A.E., 17-1, p. 73-76.)). Then the narrative focuses on the story of queen Azeb, her visit to Jerusalem, and the meeting with King Solomon, the return of Menelik I with 12 mythic kings who each received one region of Ethiopia. King •Efrem received Go• • am. (It is an interesting development of the KYbrä Naga[t).It finally ends at f. 8r-8v with the construction of MängY[to by Queen Säblä Wängel and King LYbnä DYngYl. (This part enhances the place of Go• • am and especially of MängY[to in the history of the Kingdom: this foundation appears like the third most important moment of Ethiopian history! The story of Menelik I's birth and the myth of AbrYha and AcbY% a are the most famous national myths: they are the symbol of the first and of the second Alliance of the Kings with God, with the Old and with the New Testament.) At the end of folio 8v, there is a break in the narrative marked by a seal. Then the author starts the genealogy of negu[ Täklä Haymanot. On this genealogy, the author gives developments on Queen Mentewwab and finally gives us the name of the different families who ruled Go• • am since the end of the 18 th century. Folio 9v is dedicated to the different policies practiced during the zämänä mäsafYnt. It focuses on Go• • am. Folios 10r deals with the 19 th century's policy applied south of Abbay River, folio 10v with the lords of Go• • am. Folios 10r and 11v are related to the administration of the region and to the settlement of different families in East-Go• • am: it gives their genealogy.

	.( Fiquet E.,2003,
	«Dynamiques générationnelles et Expansion des Oromo en Éthiopie au XVIe siècle », l'Homme, 3-4, Paris,
	n°167-168, p. 235-251. )
	4

  • • am, the battle of Täklä Haymanot in Mätäkäl and the marriage of his daughters. The text ends with the death of King Täklä Haymanot in 1901. 14 ras Mikä'el SYhul of Tigray gives us an example of the possibility, since the end of the 18 th century, to produce a personal chronicle next to the official's one dedicated to the ruling King. (Kropp Manfred, 1994, « La théologie au service de la rébellion -Chroniques inédites du ras Mikä'el », Etudes Ethiopiennes, Actes de la Xème Conférence Internationale des Etudes Ethiopiennes (Paris 23-26 aout 1988), Paris, Vol. 1, p. 225-236.).

  The history of Minas in Rene Basset's work is found on p. 23 and the translation is given p. 116. He uses for his studies the manuscript Paris BN Ethiopien 142 and to complete the gaps, the Paris BN Ethiopien 143. (R. Basset, 1882 « Etudes sur l'histoire d'Ethiopie », Paris, Journal Asiatique, p. 103-116) 24 Let us discuss on the versions of the Abbreviated Chronicle which do not mention the quarrel. J. Perruchon gives the difference found in the Paris BN Ethiopien 141 in comparison to the text translated in 1882 by R. Basset. (J. Perruchon, 1894(2), "Le règne de Minas", R.S., II, p. 86-90). C. Foti uses an abbreviated chronicle of Däbrä BYrhan of Gondär and Dombrowski translated the Tanasee 106. There are some different groups of Abbreviated Chronicles which are classified by region of production. As nothing is said neither on the tragic death of King Iyasu I nor on King Täklä Haymanot (1706-1708), that distinguishes the Tärika Nägä[t of MängY[to from the group of Qwäram a-Daga. (a detailed study of this group is found in the work of C. Bosc-Tiesse, 2008, ch. VI, p. 187-192).25 C. Conti Rossini, 1899, « Note per la Storia dell'Abissinia. « Il libro delle leggende e tradizioni abissine del l'Ecciaghiè Filpós », R.R.A.L., p.699. Conti Rossini dates the original period of production of this text in the middle of the 18 th century.26 These manuscripts were given to him by Prof. Gallina. 27 I.Guidi, 1926, "Due nuovi manoscritti della "Cronaca abbreviata" di Abissinia », R.R.A.L., ser. 6, vol. 2, p. 371 : • E regno Min• s Quattro anni, e quando monto sul trono, depose la sua madre, la regina • l• ni. Costei aveva costruito anteriormente, sotto il regno del suo marito Lebna Dengel, una bella chiesa chiamata Mangesta Sam• y•t, e vi raccolse molti sacerdoti dottori nei libri (nella S. Scrittura), Min•s sposo una donna e la proclamo regina. Quandi I sacerdoti di • l• ni, della chiesa da lei costruita, udirono che egli aveva deposto sua madre e fatto


Hasmik Demirkhanyan

Gagik Demirkhanyan

Edvard Kokanyan

Radik Kostanyan

Michel Aillerie

Yb 3+ doped Y 3 Al 5 O 12 , NaBi(WO 4 ) 2 and LiNbO 3 crystals as optical temperature sensors

Keywords: Optical temperature sensor, Yb 3+ doped crystal, zero-phonon spectral line

Possibilities of the use the Yb 3+ doped crystals (Y 3 Al 5 O 12 , NaBi(WO 4 ) 2 ,LiNbO 3 ) as materials for optical temperature sensor based on temperature dependences of zero-phonon spectral lines are discussed. Temperature dependences of intensities of zero-phonon transitions between individual Stark states of Yb 3+ ion due to Debye -Waller factors, homogeneous widths and shifts of the spectral lines in a range from 960 to 1060 nm are investigated. The operation temperature regions and average sensitivities for optical temperature sensors under consideration are determined.

INTRODUCTION

Recently optical temperature sensors (OTS) are in the centre of attention of many research groups, due to their high potential for applications in various fields where conventional techniques cannot be used and/or run to problems representing drawbacks for successful applications. Among the possible applications one should note temperature monitoring in highly corrosive media, electrical power stations, oil refineries, coal mines and building fire detection.

Until now a large number of distributed and point OTSs on the base of different rare-earth (RE) ions (Er 3+ , Sm 3+ , Eu 3+ , Pr 3+ ) doped glasses, ceramics and fibers have been presented [START_REF] Rai | Temperature sensors and optical sensors[END_REF][START_REF] Rai | A comparative study of FIR and FL based temperature sensing schemes: an example of Pr 3+[END_REF][START_REF] Rai | Pr 3+ doped lithium tellurite glass as a temperature sensor[END_REF][START_REF] Camargo | Infrared to visible frequency up-conversion temperature sensor based on Er 3+ -doped PLZT transparent ceramics[END_REF][START_REF] Feng | Spectroscopic properties of Er 3+ in a oxyfluoride glass and upconversion and temperature sensor behaviour of Er 3+ /Yb 3+ -codoped oxyfluoride glass[END_REF][START_REF] Li | Er 3+ -Yb 3+ co-doped silicate glass for optical temperature sensor[END_REF] . The OTSs on above mentioned materials have the ability to cover a wide temperature range (77 to 1623K) with reasonable measurement resolution [START_REF] Rai | Pr 3+ doped lithium tellurite glass as a temperature sensor[END_REF][START_REF] Zhang | Erbium-doped intrinsic fiber sensor for cryogenic temperature measurement[END_REF][START_REF] Zhang | Thulium-doped fiber optic decay-time temperature sensors: Characterization of high temperature performance[END_REF][START_REF] Singh | Ho 3+ :TeO 2 glass, a probe for temperature measurements[END_REF] . However, despite to their attractive properties, such as high temperature mechanical strength, chemical stability and excellent optical property, rare-earth doped bulk single crystals as potential materials for OTSs are less investigated.

Idea of the use of RE 3+ ions doped materials as optical sensors, including temperature ones is based on temperature dependences of spectroscopic characteristics (absorption coefficients, fluorescence intensities, fluorescence lifetimes etc.) of these materials in the infrared and visible range [START_REF] Rai | Temperature sensors and optical sensors[END_REF][START_REF] Rai | A comparative study of FIR and FL based temperature sensing schemes: an example of Pr 3+[END_REF][START_REF] Rai | Pr 3+ doped lithium tellurite glass as a temperature sensor[END_REF][START_REF] Camargo | Infrared to visible frequency up-conversion temperature sensor based on Er 3+ -doped PLZT transparent ceramics[END_REF][START_REF] Feng | Spectroscopic properties of Er 3+ in a oxyfluoride glass and upconversion and temperature sensor behaviour of Er 3+ /Yb 3+ -codoped oxyfluoride glass[END_REF][START_REF] Li | Er 3+ -Yb 3+ co-doped silicate glass for optical temperature sensor[END_REF][START_REF] Zhang | Erbium-doped intrinsic fiber sensor for cryogenic temperature measurement[END_REF][START_REF] Zhang | Thulium-doped fiber optic decay-time temperature sensors: Characterization of high temperature performance[END_REF][START_REF] Singh | Ho 3+ :TeO 2 glass, a probe for temperature measurements[END_REF] . However, as a rule, they are mainly based on fluorescence intensity ratio (FIR), when it is assumed that temperature dependence is determined only by Boltzmann factor of population of neighboring energy levels. Sensing capabilities of some materials doped with RE 3+ ions based on FIR are given in Table 1. Note that the inclusion of the Stark structure of the RE 3+ ions' optical spectra makes it possible to investigate the temperature dependences of the spectroscopic characteristics of the absorption spectra from excited Stark states, assuming (as in the case of FIR) that their population is determined only by the Boltzmann factor. This, in complete analogy to the FIR, makes it possible to consider OTS based on absorption coefficient ratio (ACR). Thus the capabilities of lithium niobate crystal doped with Yb 3+ ions as a material for OTS based on FIR and/or ACR are investigated in Ref. [START_REF] Demirkhanyan | LiNbO 3 :Yb 3+ Crystals For Optical Temperature Sensors[END_REF] (Table1). (NBW) crystals.

SPECTROSCOPIC PROPERTIES OF Yb 3+ DOPED YAG, LN AND NBW CRYSTALS

The energy spectrum of ion Yb 3+ (4f 13 electron configuration) is composed of eightfold degenerate ground multiplet, ion in LN, YAG and NBW crystals, plotted on the basis of absorption and emission spectra are given in Fig. 1. [START_REF] Montoya | Optical characterization of LiNbO 3 : Yb 3+ crystals[END_REF][START_REF] Krupke | Ytterbium Solid -State Lasers -The first decade[END_REF][START_REF] Dubinskiy | Spectroscopy of potential laser material Yb 3+ (4f 13 ) in NaBi(WO 4 ) 2[END_REF] The main spectroscopic characteristics of LN-Yb 3+ , YAG-Yb 3+ and NBW-Yb 3+ , such as line strengths of inter Stark transitions, probabilities of radiative transitions and so on, are determined in [START_REF] Demirkhanyan | Spectral Line Intensities of Yb 3+ ion in LiNbO 3 Crystals[END_REF][START_REF] Demirkhanyan | Intensities of Inter-Stark Transitions in YAG-Yb 3+ Crystals[END_REF][START_REF] Demirkhanyan | Spectroscopic properties of the NaBi(WO 4 ) 2 :Yb 3+ crystal[END_REF][START_REF] Demirkhanyan | Temperature Dependence of Spectral-Line Intensities in YAG:Yb 3+[END_REF][START_REF] Demirkhanyan | Phonon effects on zero-phonon transitions between Stark levels in NaBi(WO 4 ) 2 :Yb 3+[END_REF][START_REF] Demirkhanyan | Temperature dependences of Spectral Line Intensities of LiNbO 3 :Yb 3+[END_REF][START_REF] Kawanaka | Dramatically Improved Laser Characteristics of Diode-Pumped Yb-Doped Materials at Low Temperature[END_REF] . In particular, temperature dependences of homogeneous widths, shifts and DWFs of the ZPLs YAG:Yb 3+ are determined in [START_REF] Demirkhanyan | Temperature Dependence of Spectral-Line Intensities in YAG:Yb 3+[END_REF] and it is shown that, in accordance to experimental data [START_REF] Kawanaka | Dramatically Improved Laser Characteristics of Diode-Pumped Yb-Doped Materials at Low Temperature[END_REF] , the intensity of the ZPLs on actual wavelengths 1030 nm "dramatically" increases, when temperature decreases up to the liquid-nitrogen values. The similar pattern is also occurred in the case of NBW: Yb 3+ and LN: Yb 3+ crystals [START_REF] Demirkhanyan | Phonon effects on zero-phonon transitions between Stark levels in NaBi(WO 4 ) 2 :Yb 3+[END_REF][START_REF] Demirkhanyan | Temperature dependences of Spectral Line Intensities of LiNbO 3 :Yb 3+[END_REF] .

Figure 1. Energy levels schemes of Yb 3+ ion and transitions in LN (solid), YAG (dash) and NBW (dash-dot) crystals

As well known within the framework of Franck-Condon approximation the matrix elements of the pure electronic transitions do not depend on the coordinates of the nuclei. Consequently, for weak electron-phonon interactions (EPIs) the profile of the ZPL can be written as

( ) ( ) T , f e S k T , I M 2 f i f i ω = ω - , ( 1
)
where k is a constant, f i S is the line strength of the pure electronic transition f i → and f(ω,T) describes the ZPL, M 2 e - is DWF that expresses the dependence of the ZPL's intensity on the change of nuclei equilibrium positions due to electronic transition. The profile of single spectral line is Lorentzian:

( ) ( ) ( ) 2 f i 2 f i o f i f i 2 1 T , f Γ + Ω - ω - ω Γ × π = ω , ( 2
)
where f i Γ , ( ) o f i ω and f i
Ω are correspondingly the homogeneous linewidth, the frequency and the shift of the ZPL transition f i → . Note that in next steps we will examine the temperature dependence of the intensity ratio of the same spectral line at different temperatures. Therefore we will not take into account the temperature dependence due to the Boltzmann factor in population of the initial level of the transition. Thus, it is assumed that the temperature dependence of the ZPLs intensity is determined by the temperature dependences of the homogeneous linewidth and the shift of the spectral line and the DWF. Thereby we can define the relative intensity of ZPL according to expression

0 cm -1 0 cm - 0 cm -1 ν 1 ( ) ( ) ( ) ( ) ( ) ( ) [ ] ( ) ( ) [ ] ( ) ( ) ( ) [ ] T M 2 T M 2 exp T T T T T T I T I T R o 2 2 o 2 2 o o o - × Γ + ε Δ Γ + ε Δ × Τ Γ Γ = = , (3)
where T 0 is a fixed temperature, ε Δ is the temperature shift of ZPL. The numerical values of homogeneous line widths, shifts and DWFs of the ZPLs under consideration at K 100 T 0 = are given on the table 2.

SENSOR CAPABILITIES OF Yb 3+ DOPED YAG, LN AND NBW CRYSTALS

The sensitivity of OTS based on measurement of a temperature dependent spectroscopic characteristic, R(T), is defined by relation 1

( ) T R R 1 T S R ∂ ∂ = . ( 4
)
As a temperature dependent spectroscopic characteristic we consider the relative intensity of ZPL defined by Eq. ( 3).

Note, that due to enough complicated temperature dependences of homogeneous widths, shifts and DWFs [START_REF] Demirkhanyan | Temperature Dependence of Spectral-Line Intensities in YAG:Yb 3+[END_REF][START_REF] Demirkhanyan | Phonon effects on zero-phonon transitions between Stark levels in NaBi(WO 4 ) 2 :Yb 3+[END_REF][START_REF] Demirkhanyan | Temperature dependences of Spectral Line Intensities of LiNbO 3 :Yb 3+[END_REF] the temperature dependence of relative intensity R(T), defined by (3), and therefore the corresponding sensitivity ( )

T S R
defined by (4) have the quite complex analytical forms. In this case of quantitative characteristics for OTS we use the average sensitivity defined by

( ) ∫ Δ = 2 1 T T R R dT T S T 1 S , ( 5
)
where

1 2 T T T - = Δ
is the length of the working temperature range, i.e. the region within which the relative intensity R(T) is varied sharply.

The temperature dependences of the relative intensities and the corresponding sensitivities for more intense ZPL of YAG-Yb 3 + , LN-Yb 3 + and NBW-Yb 3+ crystals in the wavelength range 980 -1100 nm are given in Fig. 234.

Temperature ranges within which the dependence R(T) with sufficient accuracy can be approximated by linear functions, wavelength of 1030 nm is changed by one order (Fig. 4b), while the mean sensitivity is sufficiently high 3.4 %×K -1 (Table 2) and it is not only the highest compared with the average sensitivities for the investigated materials under study in the current article, but about twice exceeds the sensitivites of sensor materials listed in Table 1.

CONCLUSIONS

Thus, the Yb 3+ doped crystals can be considered as quite acceptable materials for the OTSs based on relative fluorescence method and they can be used in the development of optical temperature sensors at low temperature regions.

In the considered temperature range (40 -200 K) dependence of the relative intensity on the temperature with high accuracy (~ 0.1%) approximates by a linear function, which increases the attractiveness of these materials as OTS.

This mainly concerns to the YAG:Yb 3+ crystal, the radiation intensity temperature sensitivity of which at the wavelength of 1030 nm is "drastically" high. As a result the expected average sensitivity of the temperature sensor in the temperature range of 40 -130 К reaches a value of 3.4 %×К -1 , which in the considered temperature range on one order of magnitude exceeds the average sensitivity of cooper-constantan thermocouples (0.31 %×К -1 ) and is nearly the same as for the chromel-constantan (2.8 %×К -1 ) one. At higher temperatures (200-350K) among the considered materials are more convenient NBW:Yb 3+ and LN:Yb 3+ crystals emitting at 1010 nm wavelength with average sensitivity of 1.16 and 0.97 %×K -1 , respectively, which are about two times less in comparison with the one for cooper-constantan thermocouples -2.1 % ×K -1 . However, compared with thermocouples the OTS are contactless, provide possibilities for distance measurements and temperature monitoring in highly corrosive media, etc. Moreover, it should be noted that at high temperatures due to the Boltzmann factor the population of excited levels can be quite large and therefore OTS based on FIR, seemingly, again can be more suitable (Table 1).

  separated from each other by ~10000 cm -1 energy gap. In the crystal field the into four and three Kramers' doublets, respectively, defining thus the Stark structure of the optical spectrum of Yb 3+ ion. Energy scheme of Stark states of Yb 3+

1 Figure 2 .

 12 Figure 2. Temperature dependences of relative intensities and sensitivities of OTS based on LN:Yb 3+ : at a) 1010nm, b) 1060nm.

Figure 3 . 1 Figure 4 .

 314 Figure 3. Temperature dependences of relative intensities and sensitivities of OTS based on NWB:Yb 3+ : at a) 996.6nm, b) 1010nm.

Table 1

 1 Yb 3+ in LiNbO 3 (LN), Y 3 Al 5 O 12 (YAG) and NaBi(WO 4 ) 2

	Sensing materials	Technique: FIR or ACR		Sensitivity at 293 K, % × K-1	Temperature range, K	Ref.
	YAG:Nd 3+	FIR: 4 F 3/2 , 4 F 5/2 → 4 I 9/2	1.43	299 -523	[21]
	Silica:Sm 3+	FIR: 4 F 3/2 , 4 G 5/2 → 6 H 5/2	1.84	295 -748	[21]
	Telluride:Pr 3+	FIR: 3 P 1 , 3 P 0 → 3 H 5	1.02	273 -453	[3]
	ZBLANP:Nd 3+	FIR: 4 F 3/2 , 4 F 5/2 → 4 I 9/2	1.15	296 -473	[21]
	LiNbO 3 :Yb 3+	FIR: ACR: ν	5	4 ν , → ν → 2 ν 6 1 , ν ν ,	1 ν 5	0.43 0.48	150 -400 200 -400	[10]
	In the present paper sensing capabilities of Yb 3+ doped crystals based on temperature dependences of intensities of
	the same zero-phonon lines (ZPLs) due to the pure electron inter-Stark transition are discussed. It is assumed that
	temperature dependences of ZPL's intensities are caused by homogeneous widths, shifts and Debye-Waller factors
				2 2 F of / 5

(DWF) of corresponding transitions. Specific calculations are carried out for two more intense ZPLs caused by transitions from the ground state of excited manifold

Table 2

 2

		YAG:Yb 3+	NBW:Yb 3+	LN:Yb 3+
	Spectroscopic
	parameters	1030 nm ν 5 → ν 3	968 nm ν 5 → ν 1	996.6nm ν 5 → ν 2	1010nm ν 5 → ν 3	1010nm ν 5 → ν 2	1060nm ν 5 → ν 4
	line width at 100 K, cm -1	0.903	0.732	10.148	2.43	10.962	4.21
	Line shift at 100 K, cm -1	3.208	~ 0	-0.373	-1.19	-2.123	-0.681
	DWF at 100 K	2.755	0.007	0.942	0.82	0.175	0.352
	Linear temperature range, K	30-80	120-300	77-250	50-150	77-350	77-250
	work temperature region, K	40-130	100-240	50-400	30-350	150-350	100-350
	Average sensitivity , %× K -1	3.4	0.02	0.84	1.16	0.97	0.66

Photonics and Micro-and Nano-structured Materials 2011, edited by Rafael Kh. Drampyan, Proc. of SPIE Vol. 8414, 84140Q • © 2012 SPIE • CCC code: 0277-786X/12/$18 • doi: 10.1117/12.923453 Proc. of SPIE Vol. 8414 84140Q-1

Proc. of SPIE Vol. 8414 84140Q-2

Proc. of SPIE Vol. 8414 84140Q-3

Proc. of SPIE Vol. 8414 84140Q-4

Proc. of SPIE Vol. 8414 84140Q-5

Proc. of SPIE Vol. 8414 84140Q-6

Proc. of SPIE Vol. 8414 84140Q-7