About 595 there was an exodus of three hundred students, almost the whole student body, from the School of Nisibis. Some went to start another school, but others became monks at the nearby Great Monastery on Mount Izla in Tur ‘Abdin. This story in the Chronicle of Seert gives a hint of how monasticism, as practised in this monastery under its founder, Abraham of Kashkar, was just then in the ascendant and would take over as the dominant movement in the Persian Church. There are an ample number of Syriac sources that document this emerging movement and its leaders, and these are thoroughly surveyed, mined and cross-questioned by Florence Jullien. She sets the work of Abraham in its context, describes monastic life according to his rule and identifies the numerous disciples of Abraham and the many monastic foundations that derive from them in their turn. It turns out to be difficult to be sure what were the ‘reforming’ features of Abraham's monastery and rule, compared to earlier foundations or rules associated with Mar ‘Abda, Maruta and Rabbula. All that is clearly said is that Abraham introduced a distinctive tonsure and vestment. Probably he also introduced, gradually, a more coenobitic regime, perhaps on the basis of his own observations in Egypt. Allegiance to the ‘orthodox Fathers’ Diodore, Theodore and Nestorius was also strictly required from monks, at least according to the canons of Abraham's successor Dadisho' – an important factor, given the influential positions later assumed by monks from the Great Monastery, in the doctrinal solidity of the Church and its resistance to Miaphysite and Chalcedonian pressures.