Breton lais were certainly in existence before Marie de France chose to recast the themes that she heard from Breton minstrels into poetic narratives in Anglo-Norman verse, but she may have been the first to present a "new genre of the lai in narrative form." Her lays, are a collection of 12 short narrative poems written in eight-syllable verse that were based on Breton or Celtic legends, which were part of the oral literature of the Bretons. The lais of Marie de France had a huge impact on the literary world. They were considered a new type of literary technique derived from classical rhetoric and imbued with such detail that they became a new form of art. Marie may have filled her detailed poems with imagery so that her audience would easily remember them. Her lais range in length from 118 ("Chevrefoil") to 1,184 lines ("Eliduc"), frequently describe courtly love entangled in love triangles involving loss and adventure, and "often take up aspects of the merveilleux, and at times intrusions from the fairy world."