Acoemetae (ἀκοιμηταί, watchers), an order of monks instituted at the beginning of the fifth century by Alexander, a Syrian monk (Burger, De Acoemetis, Schneeberg, 1686). They were divided into three classes, who performed divine service in rotation, and so continued, night and day, without intermission. They were condemned by a synod held at Rome in 534 for maintaining that Mary was not the mother of God. — Helyot, Ordres Relig. 1, 4 sq.