Chrétien cites Marie de Champagne in his introduction for providing his source material, although no such texts exist today. No recorded mention of an Arthurian knight named Lancelot precedes Chrétien, but he is believed to be derived from a Celtic myth. Chrétien first mentions a character named "Lanceloz del Lac" in "Erec and Enide", who he lists third among Arthur's knights after Gawain and Erec. He next mentions him in "Cligès" where he is defeated by Cligès in a joust. An abduction of the queen is one of the oldest motifs in Arthurian legend, appearing also in Caradoc of Llancarfan's "Life of Gildas", and carved on the archivolt in Modena Cathedral. After Chrétien's version became popular, it was incorporated into the Lancelot-Grail Cycle and eventually into Thomas Malory's influential "Le Morte d'Arthur".