The Council of Chalcedon and its aftermath
Anatolius's patriarchate coincided with the doctrinal crisis over the person of Christ that the Council of Chalcedon was convened to settle. Having distanced himself from the Eutychian party that had supported his elevation, he aligned the Constantinopolitan church with the Christological confession of the council and with the position of Pope Leo I against Eutychianism.
The council's 28th canon, concerning the rank and jurisdiction of the see of Constantinople in relation to Rome, became a point of friction. Pope Leo I objected to aspects of Anatolius's conduct, including his consecration of Maximus II as Patriarch of Antioch, complaining to the Emperor Marcian and to Pulcheria.