Originally, Saint Eugenios was a pearl-fisher from the island Clysma or Kolzum near Suez in Egypt. After having worked for 25 years, he joined the monastery of Pachomius in Upper Egypt, where he worked as a baker. He is reported to have possessed spiritual gifts and worked miracles, and draw some following from among the monks. About 70 monks accompanied him when he left Egypt for Mesopotamia, where he founded a monastery on Mt. Izla above the city of Nisibis.
The location was well chosen, for Nisibis lay on the eastern edge of the Roman Empire, which had just embraced Christianity as the official religion. The rest of Mesopotamia was under Sassanid rule, which tried to revive the Zoroastrian religion and occasionally persecuted the Christian population.
A crisis occurred during the 6th century: to please the Zoroastrian rulers, the Assyrian Church decided all monks and nuns should marry. Many left the church to join the Monophysite denomination and spiritual life declined. But the reforms were soon reverted. Abraham the Great of Kashkar founded a new monastery on Mt. Izla, and he and his successor Babai the Great revived the strict monastic movement. Married monks were driven out, the teaching of the church was set on a firm orthodox basis, and Assyrian monasticism flourished for another thousand years.