At the Nestorian schism the school at Edessa was the rallying place of those who did not accept the decisions of Ephesus, but in 439 it was closed by the Emperor Zeno on account of its strong Nestorian character, and the ejected members led by Barsuma, a pupil of Ibas (d. 457), who had been the great luminary of Edessa, migrated across the Persian border. Barsuma was able to persuade the Persian king Piruz that the orthodox, that is to say the state, Church was pro-Greek, but that the Nestorians were entirely alienated from the Byzantine Empire by the harsh treatment they had received. On this understanding they were favourably received and remained loyal to the Persian monarchy in the subsequent wars with the Empire. The Nestorians re-opened the school at Nisibis and this became the focus of Nestorian activity by which an orientalised phase of Christianity was produced. Gradually the Nestorian missionaries spread through all central Asia and down into Arabia so that the races outside the Greek Empire came to know Christianity first in a Nestorian form. It seems probable that Muhammad had contact with Nestorian teachers (Hirschfeld: _New Researches._ p. 23), and certainly Nestorian monks and missionaries had much intercourse with the earlier Muslims. These Nestorians were not only anxious to teach Christianity but very naturally attached the utmost importance to their own explanations of the person of Christ. This could only be made clear by the help of theories drawn from Greek philosophy, and so every Nestorian missionary became to some extent a propagandist of that philosophy: they translated into Syriac not only the great theologians such as Theodore of Mopseustia who explained their views, but also Greek authorities such as Aristotle and his commentators because some knowledge of these was necessary to understand the theology. Much of this work of translation shows a real desire to explain their teaching, but it shows also a strong resentment against the Emperor and his state church; as that church used the Greek language in its liturgy and teaching, the Nestorians were anxious to discard Greek, they celebrated the sacraments only in Syriac and set themselves to promote a distinctly native theology and philosophy by means of translated material and Syriac commentaries. These became the medium by which Aristotle and the neo-Platonic commentators were transmitted to Asia outside the Empire, and so later on as we shall see it was a group of Nestorian translators who, by making Arabic versions from the Syriac, first brought Hellenistic philosophy to the Arabic world. But there was also a weak side, for the Nestorian Church, cut off from the wider life of Hellenism, became distinctly provincial. Its philosophy plays round and round that prevalent at the schism, it spreads this philosophy to new countries, it produces an extensive educational system, and elaborates its material, but it shows no development.