ANASTASIUS I., emperor of the east, succeeded Zeno in the year 491, and was inaugurated that same year on April the 11th. The Manicheans and Arians were greatly in hopes of being supported by the new emperor; the former because his mother was their friend, and favoured their sect; the latter because the emperor's uncle was of their opinion; but if Anastasius did not persecute them (as we do not find he ever did), yet it does not appear that he supported either of these sects. But in order to maintain the peace of the church, upon which the tranquillity of the state very much depends, he declared, that such bishops or other clergymen who should disturb the public tranquillity, by maintaining with too much heat either side of the question for or against the council of Chalcedon, should be deprived of their benefices. Accordingly the disputes concerning Eutychianism running to a very great height, and Euphemius being deeply concerned in them, the emperor expelled him from his see, and chose Macedonius in his stead. The hatred which the different parties entertained against one another occasioned often such tumults and seditions at Constantinople as threatened the life of the emperor himself; who, to keep the people in awe, ordered that the governor of the city should be present at all church assemblies and public processions. This was so much the more necessary, because these tumults were chiefly occasioned by a kind of doxology or short hymn which used to be sung at divine service. This doxology consisted only of the following words, ἀγαπεῖς ὁ Θεός, ἀγαπεῖς ἡμᾶς, ἀγαπεῖς ἀβαύρων, that is, "Holy God, holy the powerful, holy the immortal;" for which reason it was called Anaftasius, called ἀγιοποιος, Trifagius, "three times holy;" because the word holy was therein three times repeated. The orthodox used to sing that hymn without any addition, or by adding only to it, αγιος τρες, ἀγιον προς, i.e. "Holy Trinity, have mercy upon us." But Peter the Fuller, bishop of Antioch, pretended to add these words to it, viz. ἐκ σωματικῆς διὰ προσ, i.e. "who hast been crucified for us;" and as it was supposed that the first holy related to the Father, the second to the Son, the third to the Holy Ghost, the adding these words, who hast been crucified for us, seemed to intimate that the whole co-substantial Trinity had suffered; for which reason the orthodox were resolved not to admit this addition. Anaftasius desiring to have these fatal words added to that hymn whenever it should be sung at Constantinople, this occasioned a terrible sedition in the city, as though the very fundamentals of Christianity had been overthrown. Macedonius and his clergy are said to have raised that sedition, which came to such a height, that the emperor himself was obliged to come, without his crown on his head, and in a very humble manner, to the circus, where he declared to the people that he was very willing to quit the imperial throne; but he told them at the same time, that they could not all enjoy the sovereign power, which does not admit of a partnership: and that one person still must govern them if he resigned the crown. This discourse had such a power over the raging multitude, that, as if they had been divinely inspired, they immediately requested the emperor to take up his crown, promising that they would be quiet and obedient for the future. Anaftasius is by the Popish writers represented as a great persecutor of the orthodox, because he banished and deprived Euphemius and Macedonius; but they should prove that these two prelates had been unjustly banished, which is a very hard task. As to his civil government, it is confessed that at the beginning of his reign he showed himself a very good prince: he eased the people of a very heavy tax called Chrysorygum, under which they had groaned for a long time; he prohibited the fighting with wild beasts; he raised several buildings; and avoided being involved in dangerous wars as much as lay in his power. Anaftasius reigned 27 years three months and three days, or, according to F. Pagl, wanting three days; and died July the 10th, A.C. 518, in the 88th year of his age.

Anaftasius II., whose proper name was Artemius, was in the year 713 elevated to the throne of Constantinople, from the low station of a secretary, by the free voice of the senate and Roman people. His natural talents, improved by education and daily exertion, enabled him to manage with great prudence the affairs of the empire during the time that he was secretary to his predecessor Philippicus. The Saracens had made inroads upon Asia Minor, in the beginning of his reign; but he sent a strong army to the frontiers of Syria for its protection, under the command of Leo the Isaurian, a man of great military experience. These enemies of the empire also meditated the design of taking Constantinople; but the vigilance of Anaftasius defeated their purpose, by providing a formidable naval force, repairing and strengthening the walls of the city, and by forcing all the inhabitants either to provide themselves with provisions for three years, or instantly to depart from the city. Disappointed in their design, the enemy's fleet failed to Phecinia, and the imperial fleet assembled at Rhodes to watch the motions of the enemy. But the measures of the emperor received a severe check from the conduct of the sailors, who raised a mutiny, and slew their admiral for no other cause but his honourable endeavours to maintain proper discipline in the fleet. Justly dreading severe punishment, the seamen raised the standard of rebellion, declared Anaftasius unworthy to reign, and conferred the purple upon one Theodosius, a person of mean birth.

Informed of this sedition, Anaftasius fled from his tottering throne to Nice. The new emperor hastened to besiege Constantinople, which, after a feeble defence of six months, he reduced to his subjection. The late emperor being assured of his life, abandoned his claim to the crown, assumed the character of a monk, and was banished to Thessalonica, having worn the purple only during the space of two years. Having, however, prevailed upon the Bulgarians to espouse his cause, he laid aside the habit of the monk for that of the warrior, and, in the year 719, in the time of the emperor Leo, he resumed his claim to the throne. A numerous army of these barbarians hastened to the capital; but, being unable to reduce it, they delivered up the unhappy Anaftasius to the emperor, who put him to death along with his principal associates. (Anc. Un. Hist.)

Anaftasius, surnamed Bibliothecarius, a Roman abbot, library-keeper of the Vatican, and one of the most learned men of the ninth century, assisted in 869 at the fourth general council, the acts and canons of which he translated from the Greek into Latin. He also composed the lives of several popes, and other works; the best edition of which is that of the Vatican.