The eighteenth-century Wahhābī movement in central Arabia arose with the aim of combatting the Muslim cult of saints, and in so doing led to the establishment of the Saudi state. An analysis of texts authored by the movement’s founder and eponym, Muḥammad b. ʿAbd al-Wahhāb (d. 1206/1792), demonstrates that he fully adopted the tawḥīd al-ulūhiyya doctrine, together with its attendant terminology and argumentation, from Ibn Taymiyya’s writings. It was due to this doctrine that the early Wahhābīs viewed Muslims who practiced a popular cult of saints as polytheists who must be converted or conquered; in their attempt to do so, the Wahhābīs transformed Ibn Taymiyya’s theoretical and often abstruse polemic into a casus belli with real-world consequences that reverberate to this day. The early Wahhābīs’ intransigent Taymiyyan-based monolatry distinguished them from broader currents of eighteenth-century Muslim revivalism and provided a template for the radical salafī militancy of recent decades.