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 cerned 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, ἀγιοῦ Θεοῦ, ἀγιοῦ ἐχθροῦ, ἀγιοῦ ἀναστάτου, that is, "Holy God, holy the powerful, holy the immortal;" for which reason it was called τριάδικος, Triādikos, "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, ἡμῖν τριάδικος, ἐκεῖνον προσεύχεσθε, i.e. "Holy Trinity, have mercy upon us." But Peter the Fuller, bishop of Antioch, pretended to add these words to it, viz., ὁ σωτήριος διὰ μας, 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, ὁ ἀναστάτος, seemed to insinuate that the whole confessional Trinity had suffered; for which reason the orthodox were resolved not to admit this addition. Anastasius refusing to have those 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. Anastasius 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 Chrysargyrum, under which they had groaned for a long time; he prohibited the fighting with wild beasts; he raised several buildings; he avoided being involved in dangerous wars as much as lay in his power. Anastasius reigned 27 years three months and three days, or, according to F. Pagi, wanting three days; and died July the 10th, A.C. 518, in the 88th year of his age.

Anastasius, 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.