Between 318 and 323 St. Pachomius (Pakhom, Pachome and Pakhomius, Παχώμιος), a farmer once press-ganged into the army of Constantine, founded community or cenobitic organization, linking the cells of male or female hermits into monastic settlements in Upper Egypt. Beginning at Tabennisi (Tabenna,Tabennae) in the Thebaid, these monastics lived together, and had their possessions in common, under the leadership of an abbot or abbess, following an established rule, which included directions for the operation of a monastic library:
"that the books of the House are to be kept in a cupboard (fenestra) in the thickness of the wall. Any brother who wanted a book might have one for a week, at the end of which he was bound to return it. No brother might leave a book open when he went to church to meals. In the evening the officer called 'the Second,' that is, the second in command, was to take charge of the books, count them, and lock them up" (Clark, The Care of Books  54-55).
"He [Pachomius] established his first monastery between 318 and 323. The first to join him was his elder brother John, and soon more than 100 monks lived at his monastery. He came to found nine monasteries in his lifetime, and after 336, Pachomius spent most of his time at his Pabau monastery. From his initial monastery, demand quickly grew and, by the time of his death in 346, one count estimates there were 3000 monasteries dotting Egypt from north to south. Within a generation after his death, this number grew to 7000 and then moved out of Egypt into Palestine and the Judea Desert, Syria, North Africa and eventually Western Europe. Other sources maintain that the number of monks, rather than the number of monasteries, may have reached 7000" (Wikipedia article on Pachomius, accessed 11-28-2010).