Order of events in which Christianity spread across East Africa.

1. Spread of Christianity in Egypt: Christianity is believed to have reached Egypt by the first century AD, with Alexandria becoming an important center of Christian activity in the region.

2. Spread to Ethiopia: Christianity was introduced to the Kingdom of Aksum (modern-day Ethiopia) in the 4th century, making it one of the earliest Christian nations in the world.

3. Spread to Eritrea: Christianity also spread to the neighboring region of Eritrea, with the establishment of the Orthodox Tewahedo Church.

4. Spread to East African coast: Christianity began to spread along the East African coast through trade and missionary activities, with the arrival of Arab traders and missionaries from the Arabian Peninsula.

5. Spread to Kenya and Tanzania: Christianity continued to spread to the interior regions of East Africa, reaching Kenya and Tanzania by the 19th century through the efforts of European missionaries.

6. Spread to Uganda and Rwanda: Christianity gained a strong foothold in Uganda and Rwanda in the late 19th and early 20th centuries, with the conversion of local leaders and the establishment of missionary schools and churches.

7. Spread to other countries in East Africa: Christianity also spread to countries such as Burundi, South Sudan, and South Sudan, as a result of missionary activities and colonial influences in the region.

Overall, the spread of Christianity in East Africa was a gradual process that involved a combination of trade, cultural exchange, missionary work, and political factors.