Their Church split from the EasternOrthodox and Roman Catholic Churches in 451AD because of a theological dispute over the nature of Christ but is now, on most issues, doctrinally similar to the EasternOrthodoxChurch.
BBC: Christians in the Middle East debate part two
2.
Meanwhile, the spiritual leader of the EasternOrthodoxChurch, the Ecumenical Patriarch Bartholomew of Istanbul, also intervened.
CNN: Reporter held for 21 days in Iranian jails
3.
Members of the EasternOrthodoxchurch have been offended by the attempts of the Catholic church to proselytise in Russia.