Messiaen’s debt to Indian and Greek music – in particular, to the 120 desitalas systematised by the thirteenth-century theorist Sar?gadeva – is well known. The composer’s encounter with the ‘rythmes hindous’ in an encyclopedia entry led him to breakthroughs in his compositional technique from the 1930s, as he derived innovative rhythmical principles and, later, mystical associations from the rhythms over the course of his career. This chapter proposes new and broader perspectives on this subject, situating Messiaen within a history of early-twentieth-century French musical and musicological engagement with Indian music theory – a lineage including composers like Tournemire, Roussel, and Emmanuel – and complicating existing accounts of Messiaen’s rhythmic experimentation by using newly available sketch materials.