Abgar IX (179–214) did actually convert, bringing his subjects with him in the first mass conversion of Gentiles. Between 435 and 489 the Nestorians based themselves in a school in Edessa, east of the Euphrates. But when the head of that school, Narses (or Narsai, ?399–c. 503), was forced to flee to Nisibis around 471, Nestorian Christians came to be identified with Persia, the Persian church becoming officially Nestorian in 486. A school developed at Nisibis, and the see of the Nestorian Patriarch