"The Knight of the Cart" is believed to have been a story assigned to him by Marie de Champagne, and completed not by Chrétien himself, but by the clerk known as Godefroi de Leigni. A 12th-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.