I was startled a few months ago when a BBC TV documentary on Ethiopia referred to the large Muslim minority and that the communities got on well.

Ethiopia has close historical ties to all three of the world's major Abrahamic religions. It was one of the first Christian countries in the world, having officially adopted Christianity as the state religion in the 4th century. It still has a Christian majority, but a third of the population is Muslim.
Link:http://en.wikipedia.org/wiki/Ethiopia#Religion