The See of Babylon
The Babylon of his episcopate was Babylon in Egypt, the fortress district on the Nile later associated with Old Cairo, rather than the ancient Babylon of Mesopotamia. His path to it ran through the chief Egyptian see: it was the Patriarch of Alexandria who consecrated him during an errand from Sinai to Alexandria.
The synaxarion frames his episcopate as the fulfillment of an earlier prophecy spoken to him during his ascetic years, and the surviving hymnography remembers him as a teacher who preserved the doctrines of Christ and increased his congregation.