Well, if you believe "Palestine" existed, do believe then that "Trans-Jordania" existed.
From the Report by Herbert Samuel, High Commissioner and Commander-in-Chief. 30th July, 1921: officially entitled
AN INTERIM REPORT ON THE CIVIL ADMINISTRATION OF PALESTINE, during the period 1st JULY, 1920--30th JUNE, 1921.
Included in the area of the Palestine Mandate is the territory of Trans-Jordania. It is bounded on the north by the frontier of Syria, placed under the mandate of France; on the south by the kingdom of the Hejaz; and on the west by the line of the Jordan and the Dead Sea; while on the east it stretches into the desert and ends--the boundary is not yet defined--where Mesopotamia begins. Trans-Jordania has a population of probably 350,000 people. It contains a few small towns and large areas of fertile land, producing excellent wheat and barley. The people are partly settled townsmen and agriculturists, partly wandering Bedouin; the latter, however, cultivate areas, more or less fixed, during certain seasons of the year.
When Palestine west of the Jordan was occupied by the British Army and placed under a British military administration, over Trans-Jordania and a large part of Syria there was established an Arab administration, with its capital at Damascus. The ruler was His Highness the Emir Feisal, the third son of H.M. King Hussein, the King of the Hejaz. When Damascus was occupied by French troops in July, 1920, and the Emir Feisal withdrew, it was necessary to adopt fresh measures in Trans-Jordania. I proceeded to the central town of Salt on August 20th, and, at an assembly of notables and sheikhs of the district, announced that His Majesty's Government favoured the establishment of a system of local self- government, assisted by a small number of British officers as advisers.
...Five British officers were appointed to assist the councils and their officials and to aid in organising a gendarmerie. No British troops were stationed in the district. It cannot be claimed that the system of administration so set up was satisfactory. The authority of the councils was flouted by large sections of the population; taxes were collected with difficulty...
Some progress was beginning, however, to be made when, in the month of November, H.H. the Emir Abdallah, the second son of King Hussein, arrived from the Hejaz at Ma'an, to the south of Trans-Jordania. His purpose was declared to be to restore a Shereefian government in Damascus. His arrival caused much disturbance in the minds of the people of Trans- Jordania and further impaired the authority, already slight, of the local authorities. From Ma'an the Emir proceeded on March 2nd to Amman, a town on the Hejaz Railway to the east of Salt, and there established his headquarters.
The Secretary of State for the Colonies being in Palestine in the month of March, a Conference was held with the Emir, who came to Jerusalem for the purpose. An arrangement was reached by which the Emir undertook to carry on the administration of Trans-Jordania, under the general direction of the High Commissioner of Palestine, as representing the Mandatory Power, and with the assistance of a small number of British officers, for a period of six months pending a definite settlement. Order and public security were to be maintained and there were to be no attacks against Syria. Since that time a close connection has continued between Palestine and Trans-Jordania. British representatives remain in the principal centres.
I paid a visit to Amman on April 18th as the guest of the Emir...The Emir came to Palestine again in the month of May. The political and technical officers of the Palestine Administration have made frequent visits to Trans-Jordania and have assisted the local officials with their advice...The political and economic connection between Palestine and Trans-Jordania is very close...
Well, how about that.
A Saudi Arabian tried to assist his brother in Damscus (who was shifted to Iraq and you can see the two of them here in a 1923 newsclip - Abdallah is the short guy in white), threatened the French, bothered the British who then installed him across the Jordan River and in doing so, got the League of Nations to suspend the Mandate Provisions to reconstitute the Jewish national home from Trans-Jordania, making it a "country" which eventually became an "independent" Emirate in 1928 and the Hashemite Kingdom of Jordan. That Kingdon in April 1950 illegally annexed Judea and Samaria putting an end to any Arab state in the former Mandate for Palestine territory.
In 1933, TIME Magazine was aware of Trans-Jordania:
Smooth olive skin, enormous brown eyes, a close black beard and hennaed locks carefully plaited distinguish Emir Abdullah of Transjordania. Annoyed by torrid questions put to him by one of the few U. S. women he has ever received, His Highness answered coldly:
"To the desert Arab, the American or European woman is utterly devoid of charm. There is no mystery about her. She shows not only her thoughts but her bones..."
How the country looked in 1930-
and earlier. Another. A notation of a 1923 clip:
RULER OF 60 MILLION MOSLEMS The Caliph of Transjordania ( Jordan ) - King Hussein - seen inspecting his soldiers [that's Abdallah's father].
And before Abdallah came, here's how it was described in The 1911 Classic Encyclopedia update:-
>"TRANSJORDANIA, EMIRATE OF, sometimes called Kerak, a dominion extending some 200 m. S. from the Yarmuk and from the Jordan eastwards to the desert. It comprises Gilead, Amman, Moab and part of Edom of the Old Testament, and El Belga, the southern portion of the former Turkish vilayet of Damascus. After forming the independent kingdom of Ghassan under a succession of Arab dynasties from A.D. 165 onwards it was conquered by the Moslems [not, Arabs weren't originally Muslims] during the joint reigns of Amr IV. and Jabala V. and VI. in 637, and under the name of Kerak became one of the six kingdoms into which Syria was divided under the khalifs of Bagdad and the Seljuk Turks. As the Emirate of Kerak it was a separate State during the Middle Ages and again became an independent principality in 1920 with its capital at Amman (pop. 2,300). The other principal towns are Kerak (pop. 2,500), Madeba (pop. 2,000), Es Salt (pop. 8,000), Ma'an (pop.3,000), Jerash (pop. 1,500). Its inhabitants possibly number 180,000, varying according to the season and the movements of the nomads; they are partly settled Arabs - many of whom are Christians - with some colonies of Circassian Moslems and a number of nomads. It contains many interesting classical and mediaeval ruins. The physical features, flora and fauna are similar to those of southern Syria.
In 1929, we learn that
Captain Playfair, commander of the Royal Air Force at Amman. Testifying Monday Captain Playfair declared...that while...arrangements were being carried out disquieting reports were received from Amman, stating that the sheiks of Transjordania had decided to march on Palestine, being eventually restrained by Emir Abdullah, ruler of Transjordania. Upon the heels of these disquieting reports, Playfair asserted, came the Arab attack upon the police of Nablus and the raiding of Talpioth. The news of the massacre at Hebron reached him an hour after its occurrence. Nevertheless an armed tender was immediately ordered to proceed to Hebron. Enroute it encountered armed bands heading for Jerusalem. As a result the tender did not arrive in Hebron until the afternoon of the massacre. His main object, Playfair stated, was to prevent the incursion of Moslems from Transjordania, Egypt and Syria.