The Orthodox Church is a family of self-governing churches that are in full agreement with each other on matters of doctrine and are in full sacramental communion. These self-governing churches include the ancient Patriarchates of Constantinople, Alexandria, Antioch, and Jerusalem, 11 autocephalous churches, and a few autonomous churches (self-governing but not fully independent).
The Orthodox Church is hierarchical in structure and insists on the Apostolic Succession of bishops. There are three major orders – bishop, priest, and deacon – and two minor orders – subdeacon and reader. Only a bishop has the power to ordain. Priests are either ‘white’ (married) or ‘black’ (monastic). Married clergy must be married before ordination. Bishops are drawn from monastic or widowed clergy.