Eastern Orthodoxy is one of the three main branches of Christianity alongside Catholicism and Protestantism. Its theology and practices are similar to those of the early Church. Like the Pentarchy of the first millennium, the mainstream or canonical Eastern Orthodox Church is organised into autocephalous churches independent of each other from a juridical point of view. In the 21st century their number is sixteen, not counting the non-canonical ones. They choose their own primate, whose pastoral jurisdiction depends on a patriarch elected by a synod. They can have jurisdiction over other churches, only called “autonomous” because they do not designate their primacy alone.