Tirhan (East Syrian Diocese)

The Diocese of Tirhan was a diocese of the Church of the East's Province of the Patriarch. The diocese is attested between the sixth and fourteenth centuries.

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.

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