The Islamization of Jerusalem refers to the religious transformation of Jerusalem. The first Islamization of Jerusalem followed the Muslim conquest of Jerusalem under Umar ibn Al-Khattāb in 638 CE. The second Islamization followed the fall of the first Crusader Kingdom of Jerusalem in 1187, leading to an almost uninterrupted seven centuries long period of Muslim rule with a dominant Islamic culture, during the Ayyubid, Mamluk and early Ottoman periods. Beginning in the late Ottoman era, Jerusalem’s demographic turned increasingly multi-cultural, regaining a majority Jewish character during the late 19th and early 20th century that hadn’t been seen since the Roman era.