Papacy in late antiquity

The Papacy in late antiquity was a period in papal history between 313, when the Peace in the Church began, and the pontificate of Simplicius in 476, when the Roman Empire of the West fell.

He then began to interfere in various ecclesiastical matters, giving rise to Caesaropapism, and a relationship of "difficult entanglement between Church and State",[1][2] a unique characteristic of this period.

[4] The synodal organization that had been vital in the 3rd century also grew in importance at this time - through ecumenical councils called by emperors (for pragmatic and also caesaropapism reasons), to provide a definitive resolution to doctrinal disputes in the Catholic Church.

Constantine convened in 325 the First Council of Nicaea, a minimal manifestation of the belief shared by the Christian bishops,[10] which condemned Arianism, and dogmatized Trinitarianism.

It also stated in its sixth canon that it was following "ancient custom" in officiating the special powers of Rome, as well as those of Alexandria and Antioch[11] - the popes being great defenders of the Nicaea faith.

[13][15] Constantine I and the next emperors considered it their role to maintain proper worship of God, and preserve orthodoxy in their domains,[16] although they did not decide on doctrine - that was the responsibility of the bishops.

After the emperor's death, the Roman people expelled Felix, Liberius returned to Rome and annulled his decrees and reiterated his Trinitarian position, imposing it on the other western bishops.

To settle this question definitively, in 451, Emperor Marcian convened the Council of Chalcedon, which adopted Leo I's letter on the subject, Tomus I, as dogma.