Dioceses of the Church of the East to 1318
At the height of its power, in the 10th century AD, the dioceses of the Church of the East numbered well over a hundred and stretched from Egypt to China. These dioceses were organised into six interior provinces in Mesopotamia, in the Church's Iraqi heartland, and a dozen or more second-rank exterior provinces.
Source: Wikipedia — Dioceses of the Church of the East to 1318 (CC BY-SA 4.0)