The Ethiopian Orthodox Tewahedo Church (Amharic: የኢትዮጵያ ኦርቶዶክስ ተዋሕዶ ቤተ ክርስቲያን; Transliterated Amharic: Yäityop'ya ortodoks täwahedo bétäkrestyan) is the predominant Oriental Orthodox Christian church in Ethiopia. The Ethiopian Church was administratively part of the Coptic Orthodox Church until 1959, when it was granted its own Patriarch by Coptic Orthodox Pope of Alexandria and Patriarch of All Africa, Cyril VI. It should not be confused with the Ethiopian Catholic Church, which is a Chalcedonian church.
One of the few pre-colonial Christian churches of Sub-Saharan Africa, the Ethiopian Church has a membership of between 40 and 45 million, the majority of whom live in Ethiopia, and is thus the largest of all Oriental Orthodox churches. The Ethiopian Orthodox Tewahedo Church is a founding member of the World Council of Churches.
Tewahedo (Ge'ez ተዋሕዶ) is a Ge'ez word meaning "being made one" or "unified". This word refers to the Oriental Orthodox belief in the one single unified Nature of Christ; i.e., a belief that a complete, natural union of the Divine and Human Natures into One is self-evident in order to accomplish the divine salvation of humankind, as opposed to the "two Natures of Christ" belief (unmixed, but unseparated Divine and Human Natures, called the Hypostatic Union) which is held by the Roman Catholic and Eastern Orthodox churches. According to the Catholic Encyclopedia article on the Henotikon: the Patriarchs of Alexandria, Antioch, and Jerusalem, and many others, all refused to accept the Dyophysitism (two natures) doctrine decreed by the Council of Chalcedon in 451, thus separating them from the Roman Catholic and Eastern Orthodox — who themselves separated from one another later on in the East-West Schism in 1054, although not over Christological views.
The Oriental Orthodox Churches, which today include the Coptic Orthodox Church of Alexandria, the Armenian Apostolic Church, the Syriac Orthodox Church, the Malankara Orthodox Church of India, the Ethiopian Orthodox Church, and the Eritrean Orthodox Tewahedo Church, are referred to as "Non-Chalcedonian", and, sometimes by outsiders as "monophysite" (meaning "One Single Nature", in reference to Christ). However, these Churches themselves describe their Christology as miaphysite (meaning "One United Nature", in reference to Christ; the translation of the word "Tewahedo").
The Ethiopian Church claims its earliest origins from the royal official said to have been baptized by Philip the Evangelist (not to be confused with Philip the Apostle), one of the seven deacons: