Scholars of the Middle East have long searched for what they have described as the “roots” of sectarianism. But the idea that there is a stable category of religious division treats the Arab world’s religiosity as a monolith that runs uninterrupted from the medieval to modern era. In this talk, Ussama Makdisi counters this position by drawing attention to the now-obscured Arab tradition of anti-sectarianism, an ethical stance that promotes a cohesive and emancipated political community that transcends religious difference. This tradition can be seen, Makdisi argues, in calls for unity and equality between Muslim and non-Muslim Arabs during the dramatic transformations of the nineteenth-century Ottoman Empire, and in the twentieth-century secular Arab nationalist and socialist currents of the Middle East.