While little is known definitively about the life of Chrétien de Troyes, many speculative theories exist based on his work. He was employed as a writer by aristocrats of Champagne, explaining the champenois dialect detected in his work, and he usually crafted stories based on material that was presented to him. The Knight of the Cart is believed to have been a story assigned to him by Countess Marie de Champagne, and completed not by Chrétien himself, but by the clerk known as Godefroi de Leigni.
A twelfth-century French writer usually functioned as a part of a team, or a workshop attached to the court. It is believed that in the production of The Knight of the Cart, Chrétien was provided with source material (or matiere), as well as a san, or a derivation of the material. The matiere in this case would refer to the story of Lancelot, and the san would be his affair with Guinevere. Marie de Champagne was well known for her interest in affairs of courtly love, and is believed to have suggested the inclusion of this theme into the story. For this reason, it is said that Chrétien could not finish the story himself because he did not support the adulterous themes.
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.