Simplify the following text for a Grade 11 native English-speaking person.
Original: Eastern and Oriental Orthodox also recognize the Bishop of Rome as the successor Saint Peter and the Ecumenical Patriarch sends a delegation each year to Rome to participate in the celebration of his feast .
Simplified: Eastern and Oriental Orthodox do not recognize the Bishop of Rome as the successor of St. Peter but the Ecumenical Patriarch of Constantinople sends a delegation each year to Rome to participate in the celebration of the feast of Sts .