Diocese of the East

Diocese of the East Dioecesis Orientis Ἑῴα Διοίκησις
Diocese of the Roman Empire
314–535/636
The Diocese of the East c. 400.
Capital		Antioch
Historical era		Late Antiquity
•	Established	314
•	Diocese abolished by Justinian I	535 or 636
Today part of		List  Turkey  Syria  Lebanon  Israel  Palestine  Jordan  Egypt  Saudi Arabia  Cyprus

The Diocese of the East (Latin: Dioecesis Orientis, Greek: Ἑῴα Διοίκησις Heoa Dioíkesis) was a diocese of the later Roman Empire, incorporating the provinces of the western Middle East, between the Mediterranean Sea and Mesopotamia. During late Antiquity, it was one of the major commercial, agricultural, religious and intellectual areas of the Empire, and its strategic location facing the Sassanid Empire and the unruly desert tribes gave it exceptional military importance.

Its capital was at Antioch, and its governor had the special title of comes Orientis ("Count of the East", of the rank vir spectabilis and later vir gloriosus) instead of the ordinary "vicarius". The diocese was established after the reforms of Diocletian (r. 284–305), and was subordinate to the praetorian prefecture of the East.

The diocese included originally all Middle Eastern provinces of the Empire: Isauria, Cilicia, Cyprus, Euphratensis, Mesopotamia, Osroene, Syria Coele, Phoenice, Palaestina Prima, Palaestina Secunda, Arabia, and the Egyptian provinces Aegyptus, Augustamnica, Thebais, Libya Superior and Libya Inferior, which were grouped into the separate Diocese of Egypt under Valens (r. 364–378). During the course of the 4th century, several provinces were split, resulting in the new provinces of Cilicia I and Cilicia II, Syria I and Syria II Salutaris, Phoenice I and Phoenice II Libanensis (east of Mt. Lebanon), Palaestina I, Palaestina II and Palaestina Salutaris (or Palaestina III). The last creation of a new province dated in the reign of Justinian I (r. 527–565), when Theodorias, the region around Laodicea, was split off from Syria I. At about the same time, Cyprus was split off and became part of a new super-province, the quaestura exercitus.

...
Wikipedia