Before 1948, the region that is now Israel was known as Palestine and was home to a diverse population of Arabs, Jews, and Christians, as all groups had religious ties to the area, especially the city of Jerusalem. The land itself was under the control of various empires, such as the Assyrians, Babylonians, Persians, Greeks, Romans, Byzantines, and eventually the Islamic Caliphate and the Ottoman Empire. During biblical times, a postulated United Kingdom of Israel existed before splitting into two Israelite kingdoms occupying the highland zone: the Kingdom of Israel (Samaria) in the north, and the Kingdom of Judah in the south. In 1917, the region was conquered by the Ottoman Empire, which ruled it until the British conquered it in 1917. The British Mandate for Palestine officially started in 1923, and the first White Paper went into effect, capping Jewish immigration into Mandatory Palestine. In 1947, the United Nations proposed the partition of Palestine into separate Jewish and Arab states, with Jerusalem as an internationally administered city. On May 14, 1948, the State of Israel was established, marking the end of British rule in Palestine. This event triggered the first Arab-Israeli War, involving neighboring Arab countries, which ultimately led to the displacement of hundreds of thousands of Palestinian Arabs.