Dioceses of the Church of the East to 1318

There are few sources for the ecclesiastical organisation of the Church of the East before the Sassanian (Persian) period, and the information provided in martyr acts and local histories such as the Chronicle of Erbil may not always be genuine.

The ecclesiastical organisation of the Church of the East in the Sassanian period, at least in the interior provinces and from the 5th century onwards, is known in some detail from the records of synods convened by the patriarchs Isaac in 410, Yahballaha I in 420, Dadishoʿ in 424, Acacius in 486, Babaï in 497, Aba I in 540 and 544, Joseph in 554, Ezekiel in 576, Ishoʿyahb I in 585 and Gregory in 605.

These synods also dealt with diocesan discipline, and throw interesting light on the problems which the leaders of the church faced in trying to maintain high standards of conduct among their widely dispersed episcopate.

After the Arab conquest in the 7th century, the sources for the ecclesiastical organisation of the Church of the East are of a slightly different nature from the synodical acts and historical narratives of the Sassanian period.

The 14th-century writer ʿAmr ibn Mattai, bishop of Tirhan, abridged Mari's history but also provided a number of new details and brought it up to the reign of the patriarch Yahballaha III (1281–1317).

[2] The main sources for the episcopal organisation of the Church of the East during the Ummayad and ʿAbbasid periods are the histories of Mari, ʿAmr and Sliba, which frequently record the names and dioceses of the metropolitans and bishops present at the consecration of a patriarch or appointed by him during his reign.

These records tend to be patchy before the 11th century, and the chance survival of a list of bishops present at the consecration of the patriarch Yohannan IV in 900 helps to fill one of the many gaps in our knowledge.

A particularly important passage mentions the prophecy of the monastery’s superior Quriaqos, who flourished around the middle of the 8th century, that forty-two of the monks under his care would later become bishops, metropolitans, or even patriarchs.

The new status of the bishops of Rev Ardashir and Merv was recognised at the synod of Joseph in 554, and henceforth they took sixth and seventh place in precedence respectively after the metropolitan of Beth Garmaï.

The patriarch himself sat at Seleucia-Ctesiphon or, more precisely, the Sassanian foundation of Veh-Ardashir on the west bank of the Tigris, built in the 3rd century adjacent to the old city of Seleucia, which was thereafter abandoned.

It was not normal for the head of an eastern church to administer an ecclesiastical province in addition to his many other duties, but circumstances made it necessary for Yahballaha I to assume responsibility for a number of dioceses in Beth Aramaye.

As foreshadowed in the synod of Isaac in 410, Kashkar was the highest ranking diocese in this province, and the bishop of Kaskar became the 'guardian of the throne' (natar kursya) during the interregnum between one patriarch's death and the election of his successor.

[8] Instead, it merely laid down that once it became possible to appoint a metropolitan, he would have jurisdiction over the dioceses of Karka d'Ledan, Hormizd Ardashir, Shushter (Shushtra, ܫܘܫܛܪܐ) and Susa (Shush, ܫܘܫ).

In 363 the Roman emperor Jovian was obliged to cede Nisibis and five neighbouring districts to Persia to extricate the defeated army of his predecessor Julian from Persian territory.

By the middle of the 6th century there were also dioceses in the province of Adiabene for Maʿaltha (ܡܥܠܬܐ) or Maʿalthaya (ܡܥܠܬܝܐ), a town in the Hnitha (ܚܢܝܬܐ) or Zibar district to the east of ʿAqra, and for Nineveh.

[13] The bishop of Karka d'Beth Slokh (ܟܪܟܐ ܕܒܝܬ ܣܠܘܟ, modern Kirkuk) became metropolitan of Beth Garmaï, responsible also for the five suffragan dioceses of Shahrgard, Lashom (ܠܫܘܡ), Mahoze d'Arewan (ܡܚܘܙܐ ܕܐܪܝܘܢ), Radani and Hrbath Glal (ܚܪܒܬܓܠܠ).

[22] An East Syriac diocese was established in the Sassanian province of Gurgan (Hyrcania) to the southeast of the Caspian Sea in the 5th century for a community of Christians deported from Roman territory.

In 893 Eliya of Damascus listed four suffragan dioceses in the 'eparchy of Jundishapur', in the following order: Karkh Ladan and al-Sus (Susa and Karha d'Ledan), al-Ahwaz (Hormizd Ardashir), Tesr (Shushter) and Mihrganqadaq (Ispahan and Mihraganqadaq).

[37] A number of East Syriac bishops are attested between the 8th and 13th centuries for the diocese of Hebton, a region of northwest Adiabene to the south of the Great Zab, adjacent to the district of Marga.

In a casual testimony to the impressive geographical extension of the Church of the East in the ʿAbbasid period, Thomas of Marga mentions that Yemen and Sanaʿa had a bishop named Peter during the reign of the patriarch Abraham II (837–50) who had earlier served in China.

The surviving urban Christian communities in Khorasan suffered a heavy blow at the start of the 13th century, when the cities of Merv, Nishapur and Herat were stormed by Genghis Khan in 1220.

[39] Little is known about these suffragan dioceses, except for isolated references to bishops of Dinawar and Nihawand, and by the end of the 12th century Hulwan and Hamadan were probably the only surviving centres of East Syriac Christianity in Media.

A major missionary drive was undertaken by the Church of the East in Dailam and Gilan towards the end of the 8th century on the initiative of the patriarch Timothy I (780–823), led by three metropolitans and several suffragan bishops from the monastery of Beth ʿAbe.

Sin and Masin appear to refer to northern and southern China respectively, and Dabag to Java, implying that the province covered at least some of the islands of the East Indies.

In 1503 the patriarch Eliya V, in response to the request of a delegation from the East Syriac Christians of Malabar, also consecrated a number of bishops 'for India and the Islands of the Sea between Dabag, Sin and Masin'.

Damascus became the seat of an East Syriac metropolitan around the end of the 8th century, and the province had five suffragan dioceses in 893: Aleppo, Jerusalem, Mambeg, Mopsuestia, and Tarsus and Malatya.

During their journey from China to Baghdad in 1279, Yahballaha and Bar Sawma were offered hospitality by an unnamed bishop of Tus in northeastern Persia, confirming that there was still a Christian community in Khorasan, however reduced.

The only dioceses in the province of Nisibis definitely in existence at the end of the 13th century were Armenia (whose bishops sat at Halat on the northern shore of Lake Van), Shigar, Balad, Arzun and Maiperqat.

The blame for the destruction of the Christian communities east of Iraq has often been thrown upon the Turco-Mongol leader Timur, whose campaigns during the 1390s spread havoc throughout Persia and Central Asia.

Few Christian graves have been found later than the 1340s, indicating that the isolated East Syriac communities in Central Asia, weakened by warfare, plague and lack of leadership, converted to Islam around the middle of the 14th century.