“Orthodox Christianity is not new to Africa. According to tradition, the Evangelist Mark arrived on the continent around A.D. 43, and founded the Church of Alexandria and, by extension, all Africa. But “all Africa,” for most of the church’s history, effectively ended at the Sahara. Orthodox missionaries sat out the 19th century’s “scramble for Africa,” when European Catholics and Protestants fanned out across the continent to save souls and build colonies. The story of how the Alexandrian Church came to have an affiliate in faraway Uganda, a country with no previous connection to the Orthodox world, is therefore not a tale of white men bearing the message of God to a dark continent. Rather, the Ugandan church traces its roots to two Africans who, rebelling against colonial rule, fled to a religion they felt was pure and politically uncompromised. This makes Uganda’s small community of 60,000 Orthodox Christians nearly unique within their home country. They found their faith on their own.”
Read more, from One:
http://www.cnewa.org/default.aspx?ID=3211&pagetypeID=4&sitecode=HQ&pageno=1

I’ve always wondered why the Ethiopians never tried to evangelize…
Because it took time for Christianity to REALLY take root there, and by the time it did, Muslims came, and essentially surrounded them for centuries.
Perhaps being surrounded by Muslims and pagans had a dampening effect; hard to evangelize when you are holding on for dear life. Then again, they were not fully independent until modern times; their presiding bishop always came from Egypt.
Independence has nothing to do with evangelising. It’s not easy to evangelize, especially in an Orthodox manner. If you look back, most evangelists were people who evangelized in their own language, or if they evangelized in other languages, they had to be VERY well versed in foreign languages, and in how to learn them, The simple fact is, such technical knowledge wasn’t present in Ethiopia (or in most other places, until very recently).
Also, there are orthodox missions in other places in Africa. In South Africa, what was originally a Serbian Orthodox church, built for Serbian expats, became a mission once locals started becoming interested. Now there are even local priests, who were sent to study in Europe, and ordained. It’s going really well.