Orthodox Church of the East was an ancient Orthodox Church existed in the Eastern lands centered at Persia. Basically Oriental Orthodox in christology after the 5th Century following the Council of Chalcedon, this church competed with the Nestorian Church in Persia. The church was headed by Catholicos of the East .The Catholicos was also known as the Mapriyano to distinguish it from the Nestorian Catholicos who later adopted the title of the Patriarch of Baghdad. The Orthodox Catholicos exercised jurisdiction over all Orthodox Christians in the East outside the Roman Empire.