With the break-up of the Ottoman Empire at the end of World War I, the League of Nations created French Mandate Syria and British Mandate Palestine. 80% of the British Mandate of Palestine was East of the Jordan river, or “Transjordan” (as opposed to “Cisjordan”). In 1921, the British gave semi-autonomous control of Transjordan to the Hashemite family, who had lost their civil war with the House of Saud for control of Mecca and Medina.

The Hashemites continued to rule Transjordan until after World War II. In 1946, the British requested that the United Nations approve an end to British Mandate rule in Transjordan Palestine. Following this approval, the Parliament proclaimed King Abdullah the first ruler of the Hashemite Kingdom of Jordan.