Arab Christians, forming Greek Orthodox and Greek Catholic communities, are estimated to be 520,000 in Israel and around 50,000 in Palestine.
Also, there were Christian influences coming from Ethiopia in particular in pre-Islamic times, and some Hejazis, including a cousin of Muhammad's wife Khadija bint Khuwaylid, according to some sources, adopted this faith, while some Ethiopian Christians may have lived in Mecca.
Following the fall of large portions of former Byzantine and Sasanian provinces to the Arab armies, a large indigenous Christian population of varying ethnicities came under Arab Muslim dominance.
There were many Arab tribes which adhered to Christianity beginning with the 1st century, including the Nabateans and the Ghassanids.
Nabateans were possibly among the first Arab tribes to arrive to the Southern Levant in the very late first millennium BC.
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