The Sacramentary of Serapion of Thmuis is a work of Saint Serapion (fl. ca. 330 to 360, feast day: March 21[1]), bishop of Thmuis (today Tell el-Timai) in the Nile Delta and a prominent supporter of Athanasius in the struggle against Arianism. He is sometimes called Serapion the Scholastic for his learning. He is best known in connection with this prayer-book or sacramentary (euchologion) intended for the use of bishops.[2]
The sacramentary includes the earliest recorded use of the Sanctus.[3]