Texts centred on the mother of Jesus abound in religious traditions the world over, but thirteenth-century Old French lyric stands apart, both because of the enormous size of the Marian cult in thirteenth-century France and the lack of critical attention the genre has garnered from scholars.As hybrid texts, Old French Marian songs combine motifs from several genres and registers to articulate a devotional message. In this comprehensive and illuminating study, Daniel E. O'Sullivan examines the movement between secular and religious traditions in medieval culture that Old French religious song embodies. He demonstrates that Marian lyric was far more than a simple, mindless imitation of secular love song. On the contrary, Marian lyric participated in a dynamic interplay with the secular tradition that different composers shaped and reshaped in light of particular doctrinal and aesthetic concerns. It is a corpus that reveals itself to be far more malleable and supple than past readers have admitted.With an extensive index of musical and textual editions of dozens of songs, Marian Devotion in Thirteenth-Century French Lyric brings a heretofore neglected genre to light.