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.
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.
[17] The bishop and archdeacon Brikhishoʿ of Tirhan was present at the consecration of the patriarch Yahballaha III in 1281.
[19] 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.
[20] 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 c. 800, and of Rabban Babai, famous as a teacher and builder of schools in the early decades of the eighth century.
[21] 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.