Tirhan (East Syriac diocese)

The Diocese of Tirhan was an East Syriac diocese of the Church of the East, within the central ecclesiastical Province of the Patriarch. The diocese is attested between the sixth and fourteenth centuries.
History.
The Nestorian diocese of Tirhan was founded in the sixth century, probably to counter the influence of the important Jacobite (Oriental Orthodox) centre of Tagrit. The first-known bishop of Tirhan, Bar Nun, was among the signatories of the acts of the synod of Aba I in 544.
The Tirhan district lay to the southwest of Beth Garmai, and included the triangle of land between the Jabal Hamrin (known to the Nestorians as the mountain of Uruk) and the Tigris and Diyala rivers. Its chief town was Gbiltha. The diocese of Tirhan was probably included in the Province of the Patriarch instead of the province of Beth Garmai because Seleucia-Ctesiphon was closer to Gbiltha than Kirkuk (the metropolitan seat of Beth Garmai), and could be conveniently reached by water.
The bishop Sliba-zkha of Tirhan, who flourished during the reign of the patriarch Yaʿqob II (753–73), secured permission from the Jacobite authorities for the construction of a Nestorian church in Tagrit, in return for the restoration to the Jacobites of a church in Nisibis that had earlier been confiscated by the Nestorians.
The last-known bishop of Tirhan, Shemʿon, subscribed to the acts of the synod of Timothy II in 1318. (The Nestorian author Sliba ibn Yuhanna, who flourished around the middle of the fourteenth century, was wrongly claimed by Assemani as a bishop of Tirhan.) The diocese probably lapsed around the middle of the fourteenth century, and is certainly unlikely to have survived into the fifteenth century. The centuries-old status of Tagrit as the residence of the Jacobite maphrians was ended in 1393, when the town was destroyed by Timur Leng. Timur’s troops also devastated the Tirhan district. These campaigns scattered the surviving Christian communities in Tirhan, and there are no later references to either Nestorian or Jacobite Christians in the district.
Bishops of Tirhan.
The bishop Bar Nun of Tirhan was among the signatories of the acts of the synod of Aba I in 544.
The bishop Abraham of Tirhan was among the signatories of the acts of the synod of Ishoʿyahb I in 585.
The bishop Piroz of Tirhan was among the signatories of the acts of the synod of Gregory in 605.
The bishop Sargis of Tirhan was among the signatories of the acts of the synod of Dairin in 676.
The bishop Pethion of Tirhan was appointed by the patriarch Sliba-zkha (714–28). He was elected patriarch in 731.
The bishop Sliba-zkha of Tirhan flourished during the reign of the patriarch Yaʿqob II (753–73). He is first mentioned in 753, when he was imprisoned along with Yaʿqob during the brief reign of the anti-patriarch Surin. After his release he 'began to restore the churches in Tirhan', and also won permission from the Jacobite authorities for the construction of a Nestorian church in Tagrit, in return for the restoration to the Jacobites of the church of Mar Domitius in Nisibis. This agreement, which required the consent of the Jacobite maphrian Paul of Tagrit and the Nestorian metropolitan Cyprian of Nisibis, must have been concluded no later than 757, the date of Paul's death. 
The bishop Sliba-zkha of Tirhan, almost certainly the same man, was among the signatories of the acts of the synod of Timothy I in 790.
The patriarch Sargis (860–72) appointed his disciple Qayyoma bishop of Tirhan, and later appointed him metropolitan of Nisibis, replacing him as bishop of Tirhan with the teacher Yohannan.
The future patriarch Eliya I (1028–49) was bishop of Tirhan when Eliya Bar Shinaya completed his "Chronography" in 1018/19, and was commended by him as 'a profound and experienced student of church doctrine and the art of rhetoric'.
The bishop Makkikha, son of Shlemun, of Tirhan, was consecrated by the patriarch Sabrishoʿ III shortly after his consecration in 1063/4. He was present at the consecration of the patriarch ʿAbdishoʿ II in 1074. He was consecrated metropolitan of Mosul by ʿAbdishoʿ II in 1085, following the death of the metropolitan Yahballaha of Mosul, and became patriarch in 1092 on ʿAbdishoʿ's death.
The bishop ʿAbdishoʿ of Tirhan was present at the consecration of the patriarch Makkikha I in 1092.
The bishop Narsai of Tirhan was present at the consecration of the patriarch Sabrishoʿ IV in 1222.
The bishop and archdeacon Ishoʿyahb of 'al-Hazira', a town to the south of Samarra which Fiey argued was then the seat of the bishops of Tirhan, was present at the consecration of the patriarch Makkikha II in 1257.
The bishop and archdeacon Emmanuel of Tirhan was present at the consecration of the patriarch Denha I in 1265.
The bishop and archdeacon Brikhishoʿ of Tirhan was present at the consecration of the patriarch Yahballaha III in 1281.
The bishop Shemʿon of Tirhan was present at the consecration of the patriarch Timothy II in 1318.
Topographical survey.
There were several important areas of Christian settlement in the Tirhan district, including the towns of Awana, Gbiltha, Karka d'Piroz, Tagrit and Samarra, and the smaller localities of Harba and ʿAlth. 
The Nestorian ascetic Mar Sabrishoʿ of Beth Qoqa, who founded the celebrated monastery of Beth Qoqa near Erbil towards the end of the sixth century, was a native of Awana.
Shahdost of Tirhan was a noted Nestorian author, probably of the seventh or eighth century, who wrote a polemical work 'on the reasons for the separation between the Easterners and the Westerners'. Shahdost is included in the famous list of Nestorian authors compiled at the start of the fourteenth century by the metropolitan ʿAbdishoʿ bar Brikha of Nisibis.
Gbiltha, described by Thomas of Marga as 'an orthodox [i.e. Nestorian] town in the district of Tirhan', was the birthplace of Quriaqos, the Nestorian bishop of Balad , and of Rabban Babai, famous as a teacher and builder of schools in the early decades of the eighth century.
The Nestorian patriarch Sliba-zkha (714–28) was a native of Karka d'Piroz or Karkani (as the town was called in the thirteenth century) in the Tirhan district.
Tagrit, the seat of the Jacobite maphrians since the seventh century, had a small Nestorian community, first mentioned around the middle of the eighth century. In 757 or a little earlier the Jacobite authorities granted the Nestorians permission to build a church in Tagrit in return for the restoration of the church of Mar Domitius in Nisibis, a Jacobite church confiscated by the Nestorians several decades earlier. Construction of the Nestorian church began in 767, on a site by the Tigris adjacent to the city's outer wall, and the church was still in existence towards the end of the thirteenth century, when it was remarked upon by Bar Hebraeus. The Nestorian community in Tagrit was never large (Tagrit had ten Jacobite churches in the thirteenth century, but only a single Nestorian church). It probably survived until 1393, when the city was sacked by Timur Leng. Tagrit is not mentioned again as a Christian centre, and both its Nestorian and Jacobite communities were probably destroyed at this period.
The patriarch Makkikha I (1092–1110), who was earlier bishop of Tirhan, is said to have performed a miracle to rid the Tirhan district of a lion that was infesting the countryside around Harba and ʿAlth. He also cursed a Moslem who had taken stones from a Christian church in Samarra to build a mosque, and his curse resulted in the offender's death seven days later.