At the start of the 20th century the Ottoman Empire controlled what is now Jordan and Iraq, with the interior further south consisting of loosely organised Arab groupings, occasionally forming emirates, most prominent of which was the Emirate of Nejd and Hasa ruled by the al-Saud family. During the First World War an Arab Revolt, supported by Britain, succeeded in removing the Ottomans from most of the Middle East. As a result of the secret 1916 Anglo-French Sykes-Picot Agreement Britain gained control of the Ottoman Vilayets of Mosul, Baghdad and Basra, which it organised into the mandate of Iraq in 1920, and also the southern half of the Vilayet of Syria (roughly, modern western Jordan). This latter area was contested between Britain, the newly-formed Arab Kingdom of Syria, Zionists in the Mandate of Palestine, and Ibn Saud's new kingdom Saudi Arabia, resulting in a confused period in which the region was essentially an ungoverned space. Eventually in 1921 Britain declared a mandate over the region, creating the Emirate of Transjordan, under the semi-autonomous rule of King Abdullah I.