Orsisius was an Egyptian monk and author of the fourth century.

Biography

He was a disciple of Pachomius

Pachomius

Saint Pakhom , also known as Pachome and Pakhomius , is generally recognized as the founder of Christian cenobitic monasticism. In the Coptic churches his feast day is celebrated on May 9...

 on the Island Tabenna

Tabenna

Tabenna is considered the first cenobitic monastery. It was a community founded by Pachomius on an island of the Nile in Upper Egypt....

 in the Nile. When Pacomius died (348), Orsisius was chosen as his successor; but he resigned in favour of Theodore.
It was not till Theodore's death (c. 380) that Orsisius, advised by St. Athanasius, accepted the abbatial office of hegumen

Hegumen

Hegumen, hegumenos, igumen, or ihumen is the title for the head of a monastery of the Eastern Orthodox Church or Eastern Catholic Churches, similar to the one of abbot. The head of a convent of nuns is called hegumenia or ihumenia . The term means "the one who is in charge", "the leader" in...

.

Writings

Theodore and Orsisius are said to have helped Pachomius in the composition of his rule; Gennadius mentions another work:

Oresiesis the monk, a colleague of Pachomius and Theodore, perfectly learned in the Scriptures, composed a Divinely savoured book containing instruction for all monastic discipline, in which nearly the whole Old and New Testaments are explained in short dissertations in as far as they affect monks; and shortly before his death he gave this book to his brethren as his testament.

This is supposed to be the work "Doctrina de institutione monachorum" translated by St. Jerome into Latin Migne prints after it another work attributed to the same author: "De sex cogitationibus sanctorium", which, however, is probably by a later Oresius.