Oresiesis-Heru-sa Ast

Horsiesios, the name appears in the sources as Orsisius, Oresiesis, and Horsiesius, and it is Egyptian, meaning 'Horus, son of Isis', was an Egyptian monk of the fourth century who twice led the great federation of monasteries founded by Pachomius.

He came from the region of the Thebaid in Upper Egypt and joined the Pachomian communities as a young man. When Pachomius died in the plague of 348, leadership passed to Petronius, who died within months, and then to Horsiesios.

His first term went badly. The Pachomian federation had grown into something like nine monasteries and two convents, with thousands of monks, land, boats, and workshops, and the wealth brought exactly the trouble a monastic founder would expect. The head of one large house, Apollonius of Monchosis, refused to submit to Horsiesios and began running his monastery for profit. Horsiesios, unable to hold the community together and unwilling to force it, resigned and withdrew to a small house at Šeneset, the place where Pachomius had first been baptised. He named Theodore of Tabennese, Pachomius's closest disciple, in his place.

Theodore ran the federation for about eighteen years and always insisted that he was only acting for Horsiesios. When Theodore died in 368, Horsiesios came back and led the communities until his own death, generally placed around 380.

He wrote. Several letters survive, along with instructions and, most importantly, the work Jerome translated into Latin as the Liber Orsiesii, the Book of Horsiesios, which the manuscripts call his testament. It is the farewell address of an old abbot to the monks he is leaving, and it is one of the most substantial pieces of monastic teaching to come out of fourth-century Egypt.

Its theme is fidelity. Horsiesios goes back over the words of Pachomius, quotes Scripture at length, he is saturated in it, especially the prophets and Paul, and warns against the two failures he had watched destroy the peace of the houses: monks who obey the rule outwardly while their hearts are elsewhere, and superiors who use their office to enrich their own monastery. He tells the leaders that they will answer for every soul entrusted to them. He tells the monks that the strength of the community is not its buildings.

The book was read in the West because Jerome translated it, along with the Pachomian Rule, at the request of Latin monks who wanted to know how the Egyptians actually lived. Through that translation Horsiesios reached Benedict's world.

The Coptic Orthodox Church honours him as a saint.

Sources: The Book of Horsiesios and the Pachomian letters, in Armand Veilleux, Pachomian Koinonia (three volumes); Jerome's Latin translation of the Pachomian corpus; Palladius, The Lausiac History; the Coptic and Greek Lives of Pachomius.