Serapion the Sindonite was a wandering ascetic of Egypt whose life is preserved in the Lausiac History of Palladius of Helenopolis. He is surnamed "the Sindonite" because, apart from a single garment of coarse linen called a sindon, he wore no clothing; this one cloth was, by tradition, his only possession. Rather than settling in a fixed monastic community, he practised an itinerant asceticism, living, as the accounts put it, "like the birds of the air," without shelter and often fasting for days at a time.
The synaxarion relates that Serapion gave away even the sindon he wore: encountering a beggar shivering in the cold, he stripped off his one garment and was himself left naked. According to the tradition recorded by Palladius, he had earlier been given a cloak, a tunic, and a Gospel book, and he gave each of these away to the poor in turn; asked who had stripped him, he is said to have pointed to the Gospel and answered that it was this which had stripped him, and he afterward sold the book itself to relieve a debtor.
His most distinctive deed in the tradition is that he sold himself into slavery in order to win his masters to Christ. He is said to have sold himself to a Greek actor for twenty pieces of money, living on bread and water in that service until he had converted the man and his whole household to Christianity; when the actor afterward offered him recompense, Serapion departed without taking any of it. The tradition recounts a similar service of two years to a Manichaean, whose household he likewise brought to the faith.
The anchor sources place Serapion in Egypt and commemorate him on May 14 and March 21. He is to be distinguished from Saint Serapion, Bishop of Thmuis, a separate fourth-century Egyptian figure with whom he is sometimes confused.