ACÈMETI. — That is, the “sleepless ones” (ἀκούμητοι): ascetics so called because, divided into various shifts, they continuously took turns reciting the liturgical prayers. They were established by St. Alessandro the Acemeta, of Constantinople. They first resided at the Irenaion (today Cibukli) on the Asian shore of the Bosporus, and later at Constantinople in the monastery of Studios.
The most illustrious among them was St. Marcello, a disciple of Alessandro. The A. played an effective part in the theological controversies of the fifth and sixth centuries, as defenders of orthodoxy, especially against the emperor Anastasio and the empress Teodora.
Indeed, it was the A. who denounced to Pope Felice III the patriarch Acacio, who had dared to read the name of the Monophysite Pietro Mongo on the diptychs during the liturgy, at which the papal legates were also present. The latter were consequently excommunicated by the Pope, who deposed the patriarch (484).
Another occasion to defend orthodoxy arose for the A. when certain monks from Scythia Minor (today Dobrugia) proposed at Constantinople (519) the formula “One of the Trinity suffered in the flesh,” orthodox in itself, which, according to them, ought to reconcile the Tome of Leone with the anathemas of Cirillo. The formula nevertheless aroused the suspicions of the A., who attacked the Scythian monks; these went to Rome to present their ideas to Pope Ormisda. After fourteen months (June 519–62, 520) of their unsettled stay in Rome, he sent them back to the East, declaring in a letter to the emperor Giustiniano and the patriarch Epifanio that the Christological formula they advocated was superfluous in view of that adopted by the Council of Chalcedon.
The anti-Monophysite position of the A. eventually drove them toward the Nestorian heresy, inasmuch as, in vindicating the two natures, divine and human, in Christ, they went so far as to obscure the divine character of his one Person; they implicitly did so by denying, like the Nestorians, the title of Mother of God (Θεοτόκος) to the Virgin. Pope Giovanni II, at the formal request of Giustiniano, pronounced a sentence of condemnation against them (24 March 534).
After this time the A. disappear from history. They were succeeded in the monastery of Studios and in the reform of monastic life by the Studite monks under the direction of the hegumen St. Teodoro.