The Coptic Orthodox Church of Alexandria, also known as the Coptic Church, is an Oriental Orthodox Christian church based in Egypt, Africa, and the Middle East, founded in 42 AD by Mark the Evangelist. Due to disputes concerning the nature of Christ, it split from the rest of Christendom after the Council of Chalcedon in 451, resulting in a rivalry with Greek Christianity. From the 4th to 7th centuries, the Coptic Church gradually expanded due to the Christianization of Axum, Nobatia, and Alodia, while Orthodox Makuria later adopted Miaphysitism instead. After 639, Egypt was ruled by Islamic conquerors from Arabia, and the treatment of Coptic Christians ranged from tolerance to open persecution. During the 12th century, it relocated its seat from Alexandria to Cairo, and the Copts of Egypt became a religious minority. During the 14th and 15th centuries, Nubian Christianity was surpassed by Islam. In 1959, the Ethiopian Tewahedo Orthodox Church became an autocephalous church, and, since the Arab Spring in 2011, the Copts suffered from increasing discrimination and violence.