The Islamization of Palestine occurred as a result of the Islamic conquest in 640. It was a long process that included immigration of Muslim Arabs, as well as other Muslims, from other regions, as well as conversion to Islam by some of the indigenous Christian, Samaritan and Jewish population of the area. Islam did not become the majority religion of Palestine until at least the 9th century and possibly even as late as the Mamluk era (1250–1516). This occurred simultaneously with acculturation of the locals into Arab identity and the establishment of Arabic as the lingua franca, which eventually became their sole vernacular.