19 After this all unanimously agreed that the document of the bishop of Rome fully and perfectly concorded with the creeds of Nicea and Constantinople. Nevertheless, in the fifth session at the requests of the representatives of the Emperor Marcian and the senate, a new definition of the faith was worked out by a select committee of the bishops congregated from diverse lands in the basilica of St. Euphemia. k was made up of a prologue, of the creeds of Nicea and Constantinople (which was promulgated for the first time) and of a condemnation of the doctrine of Eutyches. This rule of faith was approved by the unanimous consent of the council.
Source: Sempiternus Rex Christus (Vatican.va)