History of the Catholic Church
The Council of Ephesus in 431 declared that  Jesus was both fully man and fully God. Two decades later, the Council of Chalcedon solidified Roman papal primacy. This added to continuing breakdown in relations between Rome and Constantinople, the seat of the Eastern Church. The Monophysite disagreements over the precise nature of the incarnation of Jesus led to the first of the various Oriental Orthodox Churches breaking away from the Catholic Church.