What is Patriarch of the Church of the East?

The Patriarch of the Church of the East is the patriarch, or leader and head bishop of the Church of the East. The position dates to the early centuries of Christianity within the Sassanid Empire, and the Church has been known by a variety of names, including the Church of the East, Nestorian Church, the Persian Church, the Sassanid Church, or East Syrian.

Since 1552, rival patriarchal lines were established, traditionalist on one side and pro-Catholic on the other. In modern times, patriarchal succession is claimed from this office to the patriarchal offices of the successor churches: the Chaldean Catholic Church, the Assyrian Church of the East, and the Ancient Church of the East.