Athanasius in the context of "Maximus of Jerusalem"

The Festal Letters or Easter Letters are a series of annual letters by which the Bishops of Alexandria, in conformity with a decision of the First Council of Nicaea, announced the date on which Easter was to be celebrated. The council chose Alexandria because of its famous school of astronomy, and the date of Easter depends on the spring equinox and the phases of the moon.

The most famous of those letters are those authored by Athanasius, a collection of which was rediscovered in a Syriac translation in 1842. Festal Letters of other Bishops of Alexandria, including Cyril have also been preserved.

Christianity arrived to Africa in the 1st century AD; as of 2024, it is the largest religion on the continent. Several African Christians influenced the early development of Christianity and shaped its doctrines, including Tertullian, Perpetua, Felicity, Clement of Alexandria, Origen of Alexandria, Cyprian, Athanasius and Augustine of Hippo. In the 4th century, the Aksumite empire in modern-day Ethiopia and Eritrea became one of the first regions in the world to adopt Christianity as its official religion, followed by the Nubian kingdoms of Nobatia, Makuria and Alodia and several Christian Berber kingdoms.

The Islamic conquests into North Africa brought pressure on Christians to convert to Islam due to special taxation imposed on non-Muslims and other socio-economic pressures under Muslim rule, although Christians were widely allowed to continue practicing their religion. The Eastern Orthodox Church of Alexandria and Coptic Orthodox Church of Alexandria (which separated from each other during the Chalcedonian Schism) in Egypt and the Orthodox Tewahedo Church survived Muslim invasion. Islamization of Muslim-ruled territory occurred progressively over the next few centuries, though this process is not fully understood by historians. Restrictions on church building and demolition of churches in Egypt, along with occasional persecutions such as during the reign of al-Hakim (996–1021), put additional pressure on Copts in Egypt. In the Middle Ages, the Ethiopian Empire was the only region of Africa to survive as a Christian state after the expansion of Islam. The Ethiopian church held its own distinct religious customs and a unique canon of the Bible. Therefore, the Ethiopian church community is globally unique in that it wasn't Christianised through European missionaries, but was highly independent and itself spread missionaries throughout the rest of Africa prior to the contact of European Christians with the continent.