The future Transjordan had been part of the Syrian administrative unit under the Ottomans. It was part of the captured territory placed under the Allied Occupied Enemy Territory Administration (OETA).

Under the terms of the McMahon-Hussein correspondence and Sykes-Picot agreements, Transjordan was to be part of an Arab state or confederation of Arab states. In 1918, the British military retreated from Trans-Jordan, in an indication of their political ideas about the future of the territory, which according to their position was designated to be part of the Arab Syrian state.

In August 1919, Balfour stated that he wanted Palestine to be defined to include some of the lands lying east of the Jordan, but not the Hedjaz Railway. At the 1919 Paris Peace Conference, the British officials presented a proposal including maps showing the eastern boundary of Palestine located just 10 km east of the Jordan.

At the Peace Conference, the Zionist Organization’s claims did also not include any territory east of the Hedjaz Railway. The railway ran parallel with and about 35–40 miles (about 60 km) east of the Jordan river. The Faisal-Weizmann Agreement provided that the boundaries between the Arab state and Palestine should be determined by a commission after the Paris Peace Conference.

On 13 September 1919, a memorandum was handed from Lloyd George to Georges Clemenceau which stated that British Palestine would be “defined in accordance with its ancient boundaries of Dan to Beersheba”.

The territory east of the Jordan between Damascus and Ma’an had been ruled as part of Faisal’s Kingdom of Syria since the end of the war. The British were content with that arrangement because Faisal was a British ally and the region fell within the indirect sphere of British influence according to the Sykes-Picot agreement. They favoured Arab rule in the interior, because they didn’t have enough troops to garrison the territory. Damascus was located in the French indirect sphere of influence, and the Sykes-Picot agreement called for Arab rule there too.

The boundaries of the Palestine Mandate were not defined when it was awarded in April 1920 at the San Remo conference. In a telegram to the Foreign Office summarising the conclusions of the San Remo conference, the Foreign Secretary, Lord Curzon, stated: “The boundaries will not be defined in Peace Treaty but are to be determined at a later date by principal Allied Powers”. When Samuel set up the civil mandatory government in mid-1920 he asked to put parts of Transjordan directly under his administrative control but was declined due to London’s unwillingness to commit any significant resources to this area. Following the French occupation of Damascus in July 1920, the French, acting in accordance with their wartime agreements with Britain, refrained from extending their rule south into Transjordan. That autumn Emir Faisal’s brother, Abdullah, led a band of armed men north from the Hedjaz into Transjordan and threatened to attack Syria and vindicate the Hashemites’ right to overlordship there. In March 1921 the Colonial Secretary, Winston Churchill, convened the Cairo Conference which endorsed an arrangement whereby Transjordan would be added to the Palestine mandate, with Abdullah as the emir under the authority of the High Commissioner, and with the condition that the Jewish National Home provisions of the Palestine mandate would not apply there.[i] When France occupied Damascus in July 1920, the situation had changed dramatically. The British suddenly wanted to know ‘what is the “Syria” for which the French received a mandate at San Remo?’ and “does it include Transjordania?”.[a] British Foreign Minister Curzon ultimately decided that it did not and that Transjordan would remain independent, but in the closest relation with Palestine.

At the Battle of Maysalun on 23 July 1920, the French removed the newly proclaimed nationalist government of Hashim al-Atassi and expelled King Faisal from Syria. The French formed a new Damascus state after the Battle of Maysalun, and the area of Transjordan became for a time a no-man’s land. As a result, Curzon instructed Vansittart in August 1920 to leave the eastern boundary of Palestine undefined, stating:

“His Majesty’s Government are already treating ‘Trans-Jordania’ as separate from the Damascus State, while at the same time avoiding any definite connection between it and Palestine, thus leaving the way open for the establishment there, should it become advisable, of some form of independent Arab government, perhaps by arrangement with King Hussein or other Arab chiefs concerned.”

At the same time, British Foreign Secretary Earl Curzon wrote to the High Commissioner, Herbert Samuel, in August 1920, stating, “I suggest that you should let it be known forthwith that in the area south of the Sykes-Picot line, we will not admit French authority and that our policy for this area to be independent but in closest relations with Palestine.” Samuel replied to Curzon, “After the fall of Damascus a fortnight ago…Sheiks and tribes east of Jordan utterly dissatisfied with Shareefian Government most unlikely would accept revival.” He subsequently announced that Transjordan was under British Mandate. Without authority from London, Samuel then visited Transjordan and at a meeting with 600 leaders in Salt, announced the independence of the area from Damascus and its absorption into the mandate, quadrupling the area under his control by tacit capitulation. Samuel assured his audience that Transjordan would not be merged with Palestine. The foreign secretary, Lord Curzon, repudiated Samuel’s action.

Two months later, on 21 November, Abdullah, the brother of recently deposed King Faisal, marched into Ma’an at the head of an army of 300 men.