City Readers Digital Historic Collections at the New York Society Library

Isidore of Pelusium (Greek: Ἰσίδωρος ὁ Πηλουσιώτης, d. c.450) was born in Egypt to a prominent Alexandrian family. He became an ascetic, and moved to a mountain near the city of Pelusium, in the tradition of the Desert Fathers.

Isidore is known to us for his letters, written to Cyril of Alexandria, Theodosius II, and a host of others. A collection of 2,000 letters was made in antiquity at the "Sleepless" monastery in Constantinople, and this has come down to us through a number of manuscripts, with each letter numbered and in order. The letters are mostly very short extracts, a sentence or two in length. Further unpublished letters exist in Syriac translation.

Some of the letters are of considerable interest for the exegesis of the Greek bible. He is revered as a saint, whose feast day is February 4.