The School of Nisibis (ܐܣܟܘܠܐ ܕܢܨܝܒܝܢ, for a time absorbed into the School of Edessa) was an educational establishment in Nisibis (now Nusaybin, Turkey). It was an important spiritual centre of the early Church of the East, and like the Academy of Gondishapur, it is sometimes referred to as the world's first university. The school had three primary departments teaching: theology, philosophy and medicine. Its most famous teacher was Narsai, formerly head of the School of Edessa. The school was founded in 350 in Nisibis. In 363, when Nisibis fell to the Persians, St. Ephrem the Syrian, accompanied by a number of teachers, left the school. They went to the School of Edessa, where Ephrem took over the directorship of the school there. It had been founded as long ago as the 2nd century by the kings of the Abgar dynasty. When Ephrem took over the school, its importance grew still further. After the Nestorian Schism, when the Byzantine emperor Zeno ordered the school closed for its teachings of Nestorian doctrine, deemed heretical by Chalcedonian Christianity, the School moved back to Nisibis. The school was founded around 350 by Jacob of Nisibis (Mar Yaqub). Its model was the school of Diodorus of Tarsus in Antioch. It was an ideal location for a Syriac school: in the centre of the Syriac-speaking world but still in the Roman Empire, which had just embraced Christianity. Most of Mesopotamia was under Sassanid Persian rule, which had the ancient Zoroastrian religion as its official state-religion. The Persians soon gained Nisibis, in 363, and the school was moved westward to an existing school in Edessa, Mesopotamia, where it was known as the 'School of the Persians' (Eskuli d-Forsoye/Eskuli d-Parsaye in Edessan Aramaic/Syriac). There, under the leadership of Ephrem, it gained fame well beyond the borders of the Syriac speaking world. Meanwhile, in Antioch, Theodore of Mopsuestia had taken over the school of Diodorus, and his writings soon became the foundation of Syriac theology.