Repetitive verbal practices, such as praying the rosary, are known from various religions. Despite the popularity and the cultural significance of such practices, their historical origins and development are rarely addressed in academic literature. It is often assumed that they are in principle universal and timeless and can be explained as mere actualizations of an archetypical and inborn religious proclivity or ability. In my talk, I present first results of my research project on this topic. I argue that the historically earliest known religious practice involving the repetition of one and the same formula is that of mantra repetition, which first emerged in South Asia in the final centuries of the first millennium BCE. I hypothesize that two factors were particularly important for the popularization and spread of mantra repetition: first, its simplicity, and second, its power to alter the state of mind, i.e., its psychotropicity.