How did the Eastern Orthodox Church start?
On July 16, 1054, Patriarch of Constantinople Michael Cerularius was excommunicated, starting the “Great Schism” that created the two largest denominations in Christianity—the Roman Catholic and Eastern Orthodox faiths.
Was the first church Catholic or Orthodox?
In actual truth, the earliest would be the Christians Orthodox. The first early followers of Christ are called Christian in Antioch. Roman Catholic is never founded by Jesus Christ. It started from Constantine the Great, who gave rise to Roman Catholics.