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.