In 1917, the British government gave final approval for the Balfour Declaration, calling for the establishment of a Jewish homeland in historic Israel. The declaration took the form of a letter from Arthur Balfour, British Foreign Secretary, to Lord Rothschild, who had once been a member of the British Parliament. In 1922, the United States Congress formally endorsed the Balfour Declaration. In the ensuing decades, the British would slowly whittle away at their commitment -- first lopping off 80 percent of the land east of the Jordan River to create the Kingdom of Transjordan (now Jordan), and then restricting Jewish immigration and rights to purchase land to the west of the Jordan River. The volatility of the situation ultimately forced the British to withdraw from the region in 1948.