Mandatory Palestine (25 April 1920-14 May 1948) was the name given to the United Kingdom's civil administration in present-day Israel and Palestine in the Levant. It was added to the United Kingdom after the end of World War I and the defeat of the Ottoman Empire, and the Arabs felt betrayed by the division of the Middle East in the Sykes-Picot Treaty as well as the pro-Zionist views of the UK in the Balfour Declaration, and the 1936-39 Arab revolt in Palestine was crushed by the British Army as well as Jewish paramilitary groups that defended their people from the Arabs. After World War II, the United Nations decided to partition the region between equally-large Arab and Jewish satates. In 1948, the mandate declared independence as the State of Israel, leading to the Arab countries surrounding Israel (Egypt, Transjordan, Syria, Lebanon, Iraq, Yemen, Saudi Arabia, and other Arab states) sending forces to invade Israel and take over the lands. However, the Israeli War of Independence ended in an Israeli victory, with all of the Arab countries being defeated and the Jews taking over most of the lands promised to the Arabs in the agreement, with the West Bank being occupied by Jordan, the Golan Heights by Syria, and the Gaza Strip by Egypt. The breakup of Mandatory Palestine led to the Arab-Israeli Conflict, not to peace.