In 1923, the British violated the treaty and divided the "Palestine" portion of the Ottoman Empire into two areas

In 1923, the British violated the treaty and divided the "Palestine" portion of the Ottoman Empire into two areas; 27.8% of the land west of the Jordan  River was allocated to create a Jewish Palestinian National Homeland,  (including what is known today as the 'West Bank' ie of the River Jordan) and  72.2% east of the Jordan River was allocated to form an Arab Palestinian  National Homeland - called Trans-Jordan.  

In 1947, the UN in violation of International treaties, passed Resolution 181, the Partition Plan, dividing the 27.8% of Palestine into a Jewish Palestinian State and  a SECOND Arab  Palestinian State  (Trans-Jordan being the first) These were to be the Gaza Strip plus Judea-Samaria - today also termed the 'West Bank'.  

The Jewish Palestinians accepted…..... the Arab Palestinians rejected - because they wanted all of the land, both East AND West of the Jordan  River - and to get rid of all the Jews.  In doing this, the General Assembly of the UN violated the League of the  Nations' Mandate for Palestine in that it granted political rights to the Arabs in Western Palestine - ironically, the Jews accepted the plan, while the Arabs worked to prevent it. Since the Arabs rejected it and no treaty was signed by the parties, Israel's position reverts to the Terms of the 1920 San Remo Treaty which was confirmed by the 1920 Treaty of Sevres and Lausanne, which allocated Palestine for the Jewish people.  

On May 14, 1948 the Palestinian Jews declared their own State of Israel and became "Israelis." The next day, SEVEN neighbouring Arab armies, Egypt, Jordan, Syria,  Lebanon, Saudi Arabia, Iraq  and Yemen, invaded Israel. They encouraged most of the Arabs living within the boundaries of the
'newly  declared' Israel, to leave, in order to facilitate the slaughter of the Jews  -promising that they would be given all Jewish property after the 'victorious  Arab armies' won the war.  

The result of the 1948 - 1949 Israeli War of Independence  was that the never-created second Palestinian Arab State was gobbled up by (1) Egypt  (occupying the Gaza Strip) and by (2) Trans-Jordan (occupying Judea-Samaria (today termed the "West Bank" of the Jordan  River).  

1949-1967 Jordan occupied Judea/Samaria [the 'West Bank']
In the 6-day War Israel in a defensive war liberated and defeated Jordan to TAKE BACK Judea and Samaria for the JEWISH people!!

During 1950, Trans-Jordan merged the West Bank territory into itself and granted the  'Palestinian Arabs' living there Jordanian citizenship. Since Trans-Jordan was  then no longer confined to one side of the Jordan River, it renamed itself  simply "Jordan".  So, the Arabs of Palestine ended up with nearly 85% of the original territory of Palestine...  called Jordan  but in reality Jordan east of the Jordan river was the Arab "Palestinian state.  

From 1949 - 1967 When Egypt  occupied Gaza in 1949, and Jordan occupied the West Bank aka Judea and Samaria and the Ancient City of Jerusalem in 1949, no effort or any contemplation was ever made by Egypt or Jordan to support the Palestinian-Arabs to develop their own autonomy.  

In the Arab-Israeli 6-day War of 1967, Israel  in a defensive defeated the combined military forces of Egypt, Syria, and Jordan, liberating and gaining back the West Bank aka Judea and Samaria and the Ancient biblical city of Jerusalem from Jordan.