The Catholic patriarchs of the east are generally speaking the head bishops of some of the autonomous Eastern Catholic Churches. Each patriarch of the east has authority over all bishops of a particular eastern rite church. These patriarchs are elected by their synods, and must extend communion to and receive it from the other patriarchs, including the pope, before officially taking their office. In matters of discipline and practice, but not in matters of dogma, they generally follow the customs and laws of their particular church. Perhaps the most striking example is that in most Eastern Catholic Churches, ordination of married men to the priesthood is routine (although no priest may marry after ordination, and only celibate priests may become bishops). Eastern churches that are not head