Orthodox Christianity grew out the churches established by the missionary Paul in the countries surrounding the Mediterranean Sea. Separate from the rule of the Roman government and the subsequent Roman Catholic Church, Orthodox Christianity developed its own Christian traditions and liturgy.
Similar to the Catholic Church, it claims to be the actual church established by Christ through missionaries like Paul. And it believes that this lineage of churches establishes its authority.
Unlike Catholicism and Protestantism, the Orthodox Churches do not defer to a central command, headquarters or leader. Instead, they are autonomous bodies given authority to govern themselves.