Until 1974, The Ethiopian Orthodox Tewahedo Church, an independent Christian Church headed by a patriarch and closely related to the Coptic Church of Egypt, was the state church of Ethiopia.
The Ethiopian Orthodox Tewahedo Church is the only pre-colonial Christian church of Sub-Saharan Africa, it has a membership of about 40 million people (45 million asserted by the Patriarch), mainly in Ethiopia, and is therefore the largest of all Oriental Orthodox churches. (Source: http://en.wikipedia.org/wiki/Christianity_in_Ethiopia).
About 58 percent of the people of Ethiopia are Christians, and Christianity is predominant in the highlands.