Who ruled Palestine after World War 1?
If you are talking about who is occupying Palestine today, then it will be Israel. The two nations have been in conflict since 1948 and always hates each other. Palestine today is separated in 2 sides, one is Gaza strip and the other is the land on the East of Jerusalem.
Basically, Israel occupies Palestine and they want to take over Palestine because Israel believes that they deserve to own the land, and not the Palestinians.
Post World War 1 it was Britain in the name of the League of Nations. The "Palestine" of today was created by the British and French after the defeat of the Ottoman Empire.
Post World War 1, Britain and France wanted to control oil in the middle east as a strategic resource. The Ottoman Empire was defeated and dissolved and France and Britain split the Middle East into areas of influence. They created the countries of Iraq and others and put rulers in charge of them as client states. This was all covered under the Versailles Treaty.
Palestine was made an international zone because of the religious sites in it. It was given to the League of Nations who gave it back to Britain to administrate as a Protectorate. After World War 2 it was taken over by the United Nations, administrated by Britain (who wanted out) and then divided into Israel and Palestine in 1948. This didn't go so well.
Presently Jordan and Egypt have signed Peace treaties with Israel.
Since World War I Palestine has been control by England, Israel Egypt , Jordan, Syria the PLO and Hamas.
Palestine never existed until after World War I. After World War I the land was given to England as a protectorate. The League of Nations and then the United Nations granted the authority to rule Palestine to Britain
Britain had promised control of the land of Palestine to both the Arabs and the Jews because of their assistance to England in World War I. The land had been promised twice which created an impossible situation. The Jews wanted a nation controlled by Jews to prevent further persecution. The Muslim Arabs could not tolerant living in a nation not controlled by Islam.
The United Nation proposed resolving the problems by dividing the land. Part of the land occupied by both Jews and Arabs would be politically controlled by the Jews ( Israel). The other half of the land would be politically controlled by the Muslims ( to be called Palestine) Jerusalem would be controlled directly by the United Nations.
In 1948 the United Nation granted Independence to Israel as a Nation and to Palestine as a Nation. The Muslims refused to acceptance the division of the Protectorate of Palestine. Immediately after the declaration of Independence Israel was attacked by Egypt , Jordan, Syria, and Lebanon. Israel won the war and retained control of the areas granted by the United Nations.
Jordan took control of the part of Palestine granted to the Arabs west of the Jordan rivers and Jerusalem. Egypt took control of the Gaza strip and the southern portion of the part of Palestine granted to the Arabs. The Syrians took control of the Golan Heights. These Muslim nations retained political control until 1967 The original inhabitants of the land of Palestine were left with nothing.
After winning the war of 1967 Israel controlled all of the protectorate of Palestine. Limited local control was given to the Palestine Liberation Front over the lands of the West Bank and the Gaza strip. Israel then gave total political of the Gaza strip to the Palestine Liberation Front. Then with the support of Egypt, Hamas rebelled against the Palestine Liberation Front and gained political control of the Gaza strip.
Today Israel retains complete control of the United Nations partition and partial control of West Bank. The Palestine Liberation Front has limited political control of the West Bank. This control is limited by Israel which maintains a military presence in the West Bank Hamas has complete political control of the Gaza strip somewhat limited by Hamas's dependence of Egypt.