"We" didn't "convert" anyone. Again, Sudan was a Coptic Christian area since the Second Century. Aside from Animism, the "native religion" in East Africa is effectively Christianity, a Christianity that predates Lutheranism or any other European variety.

The only people who have "converted" anyone in East Africa were the Islamists who waged, and continue to wage, a centuries long campaign of religious imperialism and extermination against pagans and Christians in the region.