The Sultanate of Nejd was a result of transformation of the Emirate of Riyadh by Abdul Aziz ibn Saud, who in 1921 declared himself Sultan over Nejd and its dependencies, as a monarchy led by the House of Saud. In 1926, the Sultanate of Nejd was expanded to include the conquered Hejaz, and the political union of Kingdom of Nejd and Hejaz was declared, with Abdul Aziz ibn Saud as King.