Among the numerous innovations of the late medieval musical and poetic repertories of northern France, the refrain stands apart. The medieval refrain was a short, 1–2 verse lyric, sometimes provided with a specific melody through music notation. Refrains functioned not only as internal elements of structural repetition, as they do within modern songs; they also served as agents of intertextuality. Hundreds of these short phrases recur throughout musical and poetic works, creating elaborate networks of cross-reference. Refrains appeared in nearly every major vernacular genre. In his Roman de la Rose, Jean Renart claimed to have initiated the practice of inserting lyrics and refrains within narrative verse; romance authors continued this tradition throughout the late Middle Ages. In addition to romance, refrains are prevalent in the motet, a polyphonic musical genre that originated in the sacred repertory of organum. Thirteenth-century composers quoted refrains within motet voices, drawing intertextual connections among motets and between motets and other genres such as romances or trouvère songs. The genre of trouvère song within which refrains most often appear is the chanson avec des refrains, a strophic song genre in which each strophe is followed by a different refrain. Refrain usage was pervasive and sustained, spanning two centuries of creative activity. Because of its presence across a variety of musical and poetic genres, the refrain has been studied by musicologists and by literary scholars; both have emphasized its role in fostering the widespread formal and registral hybridity of late medieval music and poetry.