The Mandate was originally given to Britain at the San Remo conference, but it was only approved by the full League of Nations, the prelude to the United Nations, in July of 1922. The British determined the borders of Palestine according to other agreements they had made with their allies during World War 1. For example, in 1921 they renamed the eastern bank of the Jordan River Trans-Jordan and transferred limited control to the son of Hussein ibn Ali, Abdullah ibn Hussein, who ultimately became the King of Jordan. In 1946, The Kingdom of Jordan was formally declared and all control was handed to the new King. Hussein's family were Hashemites, who according to Islamic tradition from the 10th century were the 'True Keepers Of Mecca and Medina' in western Arabia, now under the rule of the Al Saud family. Until the British mandate, there was no 'third holiest site' in Islam, and the compound called Al Aqsa was not considered anything more than a mosque within the Islamic world. 

To prove this, at the turn of the 20th century, in 1908 the leader of the Hashemites, Hussein ibn Ali, was named as Sharif and Emir of Mecca by Ottoman Sultan Abdul Hamid II. The formal title was 'Ruler of The Hejaz', which encompassed Palestine, Jordan, Syria, Iraq and parts of Arabia including Mecca and Medina. In 1916, he was named 'King Of The Arab Countries' by the British after he led the Arab revolt against the Ottoman Empire. After the Ottoman's were defeated, the French moved into Syria and Lebanon and booted Ali leaving him ruler of Iraq, Palestine (including Trans-Jordan), and much of western Arabia although, with negotiations in high gear and loyalties switching almost every day, very few in the Arab world saw Ali as their King. The Temple Mount in Jerusalem was in disrepair and while several mosques were in operation, none were considered as part of Islam's holy sites and so, Hussein ibn Ali did not deploy officials there as he had to Mecca and Medina.  

Ibn Ali died in 1921 and his sons, Abdullah and Faisal were named as successors to rule over the Hejaz with Abdullah taking over Jordan and Western Arabian parts of the kingdom while Faisel ruled the southeastern part of Syria and all of Iraq. Abdullah was overthrown by Ibn Saud, who created the Kingdom of Saud (Saudi Arabia) at the end of 1924 after the British withdrew their support for the Hussein family. Faisel was killed in a coup in Iraq in 1958 when Iraq was established as an independent state.

To appease the Hashemite dynasty and allow them to save face, as well as to put facts on the ground in the face of a looming Jewish state which the Arabs were firmly against, the ruler of Saud, who had claimed western Arabia for his own, declared the Hashemites as trustees over 'the other Holy sites' such as Hebron's tomb of the Patriarchs and Jerusalem's Old City including Al Aqsa, the Dome of the Rock and even the Western Wall. He handed control over Trans-Jordan to the family so they could rule, however, the inhabitants of that land were mostly transplants from across the Levant and Mughrab (Northern Africa) who had come to help build the railways and roads that were needed to resupply troops during the war. The tribal leaders of Trans-Jordan who had been there for generations rejected a unifying king and for the most part, the area now known as Jordan was deeply divided politically with the king usually employing a heavy hand to put down dissent.

The British mandate over Palestine lasted from 1922 until May 1948 when the State of Israel was finally established. The Arab nations around what was now Israel and Palestine, that is the entire land west of the Jordan river to the Meditteranean Sea and from the southern border of Lebanon to the northern border of Sinai were against any form of Jewish presence in the area.

What was once a promise to give the Jewish nation a land of their own encompassing Judea, Samaria and all of Israel including Gaza became a decades-long negotiation. While the 'Palestinian' Arabs are practical subjects of the Jordanian King, there were Arab populations living in areas like Lod, Jerusalem, Nazareth, Haifa, and Acre and across the land. These populations were used to create a new brand of Arabs, who initially rejected the name Palestinian as in their own words 'The Jews are the Palestinians'. And so, the once promised Arab state living side-by-side with the Jewish state, which is technically Jordan, was created. This is why the original Balfour Declaration map which showed a Jewish state as the whole of Israel, the West Bank, and Gaza was carved up to where the Jews had most of the coast, and the Negev desert down to Eilat and the Palestinians had the West Bank and most of the galilee.  

The struggle to establish a Jewish state in Palestine began after the issuance of the 1917 Balfour Declaration. In this document, the British government declared its support for the establishment of a “national home for the Jewish people” in Palestine - which at the time encompassed all the land to the west of the Jordan River, and the area of Palestine that eventually became Trans-Jordan. The British Mandate for Palestine was approved by the League of Nations and incorporated some of the principles of the Balfour Declaration. However, under the terms of the mandate, Britain had a dual obligation towards both Arabs and Jews in Palestine. Much of this had to do with the naming of Al Saud as ruler of Saudi Arabia This means Britain had to conduct its policy in Palestine according to the needs of both groups. This included creating political, administrative, and economic conditions that would facilitate the independent rule of both communities under British control. These terms were a contradiction in the mandate. However, during the mandate era, these two separate social systems developed under one political framework. Each society had its own welfare, educational, and cultural institutions and they gradually became politically and economically independent of one another. During this period, the Arab population doubled and the Jewish population grew tenfold.

Arab citizens of Palestine opposed the establishment of a Jewish state in Palestine, and after the Mandate was approved, a series of violent confrontations between the Jews and the Arabs took place from the 1920s to the 1930s, costing hundreds of lives. Nevertheless, around 75,000 Jews emigrated to Palestine between 1922-1926. In 1935, about 60,000 Jews emigrated in an attempt to flee Nazi-dominated Europe.

Jewish immigration to Palestine was encouraged by the British all through the 1920s, but in the 1930s a few events such as the Great Depression and the flight of refugees from Nazi Germany led to a change in this policy. The British government proposed partitioning Palestine into mutually dependent states - one for the Arabs and one for the Jews. However, this was rejected by the Arabs who demanded that the British government halt Jewish emigration to Palestine. In turn, this led Britain to restrict Jewish immigration so that the Arabs would continue to support Britain in the war against Germany and Italy. This agreement was named the White Paper (1939).

As a result of the White Paper, Palestine was completely closed off to Jews fleeing Nazi-controlled Europe during the Second World War for five years. However, since many Jews were seeking refuge during this time, there was a lot of illegal immigration occurring which caused a deteriorating situation in Palestine with increasing violence between the Jewish and Arab communities. This brought negative views on Britain and thus the British government decided to terminate the mandate and turn the Palestine question back over to the United Nations. In 1948, the British terminated the mandate and the final decision of the UN General Assembly was to declare the independence of the State of Israel.