When Nisibis (Nusaybin) was ceded to the Persians along with the five Transtigritine provinces in 363, Ephrem the Syrian left his native town for Edessa, where he founded the celebrated School of Edessa. This school, largely attended by the Christian youth of Persia, and closely watched by Rabbula, the friend of Cyril of Alexandria, on account of its Nestorian tendencies, reached its highest development under bishop Ibas, famous through the Three-Chapter Controversy, was temporarily closed in 457, and finally in 489, by command of Emperor Zeno and Bishop Cyrus, when the teachers and students of the School of Edessa repaired to Nisibis and became chief writers of the Church of the East. Miaphysitism prospered at Edessa after the Arab conquest.