In the spring of 1952, international congresses convened in several Middle Eastern and European capitals to celebrate the thousandth birthday of the great tenth/eleventh-century Muslim philosopher Ibn Sina, known in Europe as Avicenna and across the lands of Islam as “the Preeminent Master.” Like the better-known Afro-Asian solidarity conferences being held simultaneously, these scholarly forums were sponsored by UNESCO, the Arab League, and other international organizations founded in the 1940s with mandates to usher in the new, global era heralded by the end of World War II and advent of decolonization. At the helm of the Ibn Sina millenaries was a rising generation of reformist scholars from the Muslim world who championed the Preeminent Master and his Islamic interpreters as paragons of a “new humanism” which—unlike its European counterpart—offered a truly universal philosophy of humanity by virtue of its multicultural genealogy and accommodation of religious belief. Drawing on heretofore unexamined archival records of the Ibn Sina millenaries plus the voluminous body of multilingual scholarship produced for them, my presentation situates these largely forgotten scholarly forums as generative sites in the much-discussed “humanism debate” of the postwar era. In so doing, I recast this debate—usually represented as a watershed in continental thought driven by European philosophers—as a transregional conversation that entailed not only a critical reckoning with Europe’s compromised humanist tradition, but also the creative reconstruction of Islamic thought traditions as grounds for an other humanism than that realized by Western modernity.