Held in Constantinople in 553. Under Emperor Justinian the Great. 165 Bishops were present.
Nestorian and Eutychian Controversies
The Council was called in hope of putting an end to the Nestorian and the Eutychian (Monophysite) controversies). The Council confirmed Church's teaching regarding the two natures of Christ (human and divine) and condemned certain writings with Nestorian learnings. Emperor Justinian himself confessed his Orthodox faith in a form of the famous Church hymn "Only begotten Son and Word of God" which is sung during the Divine Liturgy.
Read about the other Ecumenical Councils: