Brief accounts of Acacius's reign are given in the Ecclesiastical Chronicle of the Jacobite writer Bar Hebraeus and in the ecclesiastical histories of the Nestorian writers Mari, ʿAmr and Sliba. His life is also covered in the Chronicle of Seert.
Acacius's patriarchate
Acacius played a key role in the events that led to the takeover of the Church of the East by the Nestorians in the last two decades of the fifth century. A moderate churchman, he was appointed patriarch in 485 by the political enemies of the powerful metropolitan Barsauma of Nisibis, a champion of Nestorianism, in the hope that he would prevent the takeover of the Church of the East by the Nestorians. But despite frequent quarrels with Barsauma, Acacius was unable to prevent the victory of the powerful Nestorian faction. Synods held in Beth Edrai and Seleucia-Ctesiphon entrenchedNestorian christology within the Church of the East. The following account of Acacius's reign is given by Bar Hebraeus, who as a Jacobite author was prejudiced against the Nestorians. In the first sentence Barsauma is derisively nicknamed 'Bar Sula', 'son of the shoe'.
Then the bishops who had fled from Bar Sula met at Seleucia, and consecrated a certain Acacius as their catholicus. When Barsauma of Nisibis and Magna of Fars heard of this, they threatened to kill Acacius like his predecessor unless he accepted their words. And he, terrified, gave in to them, chiefly on account of the old affection that he still felt for them; for he had been a fellow-student of Barsauma, Magna and Narsaï in the school of Edessa, and had fled from there with them; and so he did not oppose their plans. He also convened a synod in which he confirmed the faith of Nestorius. From that time Nestorianism held sway throughout the East, and fornication became so common among the bishops, the priests, the deacons and the people that Christian babies lay on the rubbish tips and in the streets, and many of them were eaten by dogs, so that Acacius was forced to build houses to accommodate the orphans and to feed the women so that they might bring up the offspring of their lust. In this way, under tragic auspices, the Nestorian faith was established in the East.
At that time Acacius was sent by the king of the Persians as an ambassador to the emperor of the Greeks, and the western bishops met with him. He was asked about the Nestorian heresy, but denied any knowledge of either Nestorius or his heresy, and said that this was just a shameful name given to them by their enemy Aksenaya. On his return to the East, Acacius found that Barsauma had already died. Some say that the monks of Tur ʿAbdin mobbed him in the church and killed him with the keys of their cells, while others say that his tomb can be seen in the church of Mar Yaʿqob in Nisibis.