The region, according to Islamic tradition, is the birthplace of the Islamic prophet Muhammad, who was born in Mecca, which is locally considered to have been founded by the Islamic prophets and matriarch Abraham, Hagar and Ishmael. The area became part of his empire through the early Muslim conquests, and it formed part of successive caliphates, first the Rashidun Caliphate, followed by the Umayyad Caliphate, and finally the Abbasid Caliphate. The Ottoman Empire held partial control over the area; after its dissolution, an independent Kingdom of Hejaz existed briefly in 1925 before being conquered by the neighbouring Sultanate of Nejd, creating the Kingdom of Hejaz and Nejd. In September 1932, the Kingdom of Hejaz and Nejd joined the Saudi dominions of Al-Hasa and Qatif, creating the unified Kingdom of Saudi Arabia.