The Sacramentary of Serapion of Thmuis is a work of Saint Serapion, or Sarapion (fl. ca. 350), bishop of Thmuis (Modern: "Tell el-Timai") in the Nile Delta and a prominent supporter of Athanasius in the struggle against Arianism (sometimes called, for his learning, Scholasticus), is best known in connection with a prayer-book or sacramentary intended for the use of bishops.