How did Egypt's religions get into Egypt?

Answer 1

It depends on the religion.

Kemetism and Atenism were founded in Egypt, so they did not have to come from somewhere else.

Judaism came to Egypt during the times of the Persian Empire, when Jews moved freely across the Persian Empire (from Israel and Iraq to Egypt).

Greek Polytheism came to Egypt during the Hellenistic Period under Alexander the great and the Ptolemies.

Christianity came to Egypt in the 1st Century during the Roman Empire, where St. Mark supposedly planted the seed of the Church in Alexandria. When there was disagreement over the Council of Chalcedon, the Church in Egypt broke off from the Catholic and Orthodox churches and became the Coptic Church, which prevailed over much of northeastern Africa (Egypt, Sudan, Ethiopia, etc.)

Islam came to Egypt through the Islamic conquests. Egypt has shifted through various different sects of Islam. It was Kharijite during the Islamic Civil War period, became Sunni again under the Umayyads and early Abbassids, became Ismaili Shiite under the Fatimids, and reverted to Sunni under the Mamluks, the Ayyubids, the Ottomans, and the Khedivites.

Baha'i came to Egypt through proselytization and migrations from Iran in the early 20th century.

Atheism has come to Egypt in small pockets due to exposure from other places in the world through the internet. Most Atheists in Egypt were born Muslims and because of Egypt's laws on religion, are still identified as Muslims on their legal files.