Papa

Papa bar Aggai was the Bishop of Seleucia-Ctesiphon, the capital of Sassanid Persia, in the late 3rd and early 4th century. An important figure in the early history of the Church of the East, he was first in the generally recognized line of Bishops of Seleucia-Ctesiphon, who would later become the acknowledged head of the church. He was the first bishop to be given the title of Catholicos, and set about restructuring the previously disorganized Persian church. Some historians describe him as the founding figure of the Church of the East, though according to Syriac tradition, he was simply continuing a line of leaders, such as Mar Mari, that stretched back to Thomas the Apostle.