Before the First World War, Palestine was part of the Ottoman Empire. After the war, the League of Nations gave Britain a mandate to govern Palestine. During the British Mandate, Jewish immigration to Palestine increased significantly. This led to conflict with the Arab population, who feared that the Jews would eventually establish a Jewish state in Palestine.
In 1948, the British Mandate ended and the State of Israel was declared. The Arab-Israeli War of 1948-1949 followed, and Israel gained control of most of Palestine. The West Bank and Gaza Strip were occupied by Jordan and Egypt, respectively.
In 1967, Israel occupied the West Bank and Gaza Strip during the Six-Day War. Israel has since annexed East Jerusalem, and settlements have been built in the West Bank.
The Israeli occupation of the West Bank and Gaza Strip is illegal under international law. The Fourth Geneva Convention prohibits an occupying power from transferring its own civilian population into the occupied territory. Israel has violated this prohibition by building settlements in the West Bank and Gaza Strip.