While discussions of “millennial sovereignty”—notions of kingship legitimized on eschatological grounds—have focused primarily on the Persianate world of the ninth/fifteenth century and later, this paper explores indications that similar ideological avenues were explored at the court of the Mamluk sultan al-Malik al-Zahir Barquq (r. 784/1382-801/1399). The first of the post-Qalawunid, Circassian sultans, Barquq’s rise to power and reign were marked by questions of legitimacy and internal and external turmoil that were extreme even by the standards of the Mamluk period, and evidence addressed in the paper suggests that he and members of his court sought out novel means of asserting divine license for his rule. Drawing on the writings of 'Abd al-Rahman al-Bistami, Sayyid Husayn al-Akhlati, Ibn Hajar al-'Asqalani, Ibn Khaldun, and others, it is argued that a coterie of practitioners of the occult “science of letters and names” ('ilm al-huruf wa-al-asma') Barquq fostered, including many individuals of Persianate origin, helped formulate an ideology of Sufi-inflected millennial sovereignty for their patron. Beyond questions of Barquq’s embrace of such an ideological program, the paper explores the notion that eighth/fourteenth-century Cairo was an important cauldron for the formulation of these ideas that would so shape religio-political dynamics of the Persianate world.