Semi-sovereign emirate of the Hashemite sharifs of Mecca (Banu Qatadah) who ruled the holy cities of the Hejaz - Mecca, Medina and Jeddah - under nominal Ottoman suzerainty from 1517, retaining substantial autonomy until Ottoman administrative reforms after 1872 eroded it.
In 1916 Sharif Hussein bin Ali launched the Arab Revolt and proclaimed himself King of the Hejaz, transforming the emirate into the Kingdom of Hejaz (already canonical, id: kingdom_of_hejaz); the kingdom in turn fell to the Saudis in 1925.