How did the Eastsern Churches begin?
At the Last Supper Jesus gave His Apostles the Eucharist. He said to them “Do this in memory of Me”. The Apostles did just that and brought the Gospel and the Eucharist to the East. St. Peter leaving the East, went to Rome to establish the Church there. Thus, we have two branches of the Catholic Church. One is called Eastern with its many Churches, traditions and customs, and the other is called Latin or Roman. Both Eastern Catholic and Western Latin (Roman) are under the Pope and his authority.