The Ottoman forces in Medina surrendered after the war, but the end of World War I did not meant the end of hostilities in Arabia, as the Saudi forces continued to expand on all fronts. In 1920, Saud forces occupy the mountainous areas of Abha in Asir on the pretense of settling tribal disputes. In May 1921, Ha’il, the last Al Rashid stronghold, surrendered, and most of the remaining Rashidi territory was annexed to Ibn Saud. At this point he changes his title from Imam of Nejd to Sultan of Nejd.
Meanwhile, the British and the French split up the conquered Arab world between the sons of King Hussein. The British give Abdullah rule over Transjordan, a British protectorate, and gave King Faisal rule over Syria. Faisal was soon ousted by the French, who deemed the country to be within their sphere of influence, but King Faisal was lucky enough to be established as King of Iraq shortly thereafter, a country formed by the British by merging the territories of Baghdad and Basra.
* 1922: Saudi forces occupy all of Asir.
* December 2, 1922: Protocol of Uqair, defining most of the borders with Iraq and Kuwait and creating the neutral zone.
* 3 March 1924: Turkey abolishes Islamic caliphate and the title of Caliph is taken up by King Hussein of Hijaz on March 5. Ibn Saud uses this — heresey — as justification to begin total war.
* August 1924: The Ikhwan militia attack Transjordan despite Ibn Saud’s orders to the contrary. 15 kilometers off Amman they are almost entirely eliminated by the Royal Air Force, without which they most likely would have captured the city.
* 3 October 1924: King Hussein abdicates and is succeeded by his son, King Ali. Saudi forces enter Makkah unopposed less than a week later
* January 1925: Saudi siege of Jeddah begins.
* 2 November 1925: Hadda Agreement defining initial border with Jordan, negotiated by Sir Gilbert Clayton of Great Britain.
* 5 December 1925: Saudi forces occupy Medina, and on 19 December, enter Jeddah.
* 20 May 1927: Treaty of Jeddah, whereby Great Britain recognizes Ibn Saud’s sovereignty over Hejaz and Nejd, and Ibn Saud recognizes British protectorates in the Trucial States, Aden and Oman. Ibn Saud changes his title from Sultan of Nejd to King of Nejd.
* November 1927: The Ikhwan revolt against Saudi rule due to its technological modernization and raid Southern Iraq.
January 1928: The Ikhwan attack and raid Kuwait.
* 1930: Ibn Saud decisively defeats the Ikhwan at the Battle of Sabilla, near Ha’il. This was the last great bedouin battle fought on camels.
* 1932: Hejaz and Nejd, previously administered as two regions, are unified as the Kingdom of Saudi Arabia.
* 1934: After a brief war with Yemen, in which the territory of Najran agrees to join Saudi Arabia in exchange for Shia religious autonomy, the Treaty of Taif defines the boundary with South Yemen.
The British are criticized today for betraying the Arab Revolt by splitting up the Arab world into multiple states. I think this criticism is overblown and myopic. No, the British did not unify one Arab state under the rule of King Hussein, but did set up Kingdoms to be ruled by each of his sons, most of whom were overthrown by the locals. Surely this was the better outcome.