According to Islamic prophetic tradition, Muhammad was descended from Adnan. Tradition records the genealogy from Adnan to Muhammad comprises 21 generations. Various genealogies of Adnan up to Isma'il have been narrated and is subject to controversies and doubt. Adnan was the ancestor of the Adnani Arabs of northern, central and western Arabia and a direct descendant of Isma'il. It is not confirmed how many generations are between them, however Adnan was fairly close to Isma'il. Isma'il had twelve sons who are said to have become twelve tribal chiefs throughout the regions from Havilah to Shur (from Assyria to the border of Egypt). Genealogists differ from which son of Isma'il the main line of descent came, either through his eldest son Nabut, or his second son Qedar who was the father of the North Arabian Qedarite tribe that controlled the region between the Persian Gulf and the Sinai Peninsula. Genealogists also differ in the names on the line of descent.