Egyptian monk. Ran the famous catechetical school of Alexandria, Egypt. Resigned to spend more time in prayer and penitence. Spiritual student of Saint Anthony the Abbot in the desert. Friend of Saint Athanasius of Alexandria.

Bishop of Thmuis, near Diospolis in the Nile delta of Egypt in 339. Fought Arianism. Supporter of Athanasius, and spoke for him in the Council of Sardis in 347. Banished by Emperor Constantius II for his opposition to Arianism. Named a Confessor of the Faith by Saint Jerome. Fought Macedonianism, which denies the divinity of the Holy Spirit. Wrote against Manichaeism, showing that our bodies can be instruments of good or evil, that it is our choice, and that just and wicked men often change; it’s therefore a lie to think our souls are of God, our bodies of the devil.

Wrote several learned letters, a treatise on the titles of the Psalms, and a sacramentary called the Euchologium, a collection of liturgical prayers. Saint Athanasius wrote several works against Arians at Serapion’s request, but thought so much of Sarapion that he told him to revise them as he saw fit.