The first recorded reference to Sir Lancelot in all of Arthurian literature is his appearance as the title character in Chrétien de Troyes romance, Lancelot, written about 1190. This makes Lancelot one of the latest additions to the Arthurian tradition of all the major characters.

Although several scholars have sought precursors to Lancelot in the Celtic sources, the weight of opinion seems to favor the idea that Chrétien fabricated Lancelot as a wholly new character in the Arthurian world. Indeed there is some bit of textual evidence that may suggest Lancelot was created at the behest of Chrétien's patroness, Marie de France, because she wanted a French knight to be the hero of the tale (the name "Lancelot" is rather French sounding, and in later tales he is often known as "Lancelot du Lac," a knight from France).

Lancelot's character and history were much further developed in the French Vulgate Cycle of Arthurian romances. It is telling that whereas in the insular versions of the Arthurian myths the Celtic Sir Gawain was usually the star and was upheld as the greatest of Arthur's knights, in the French romances the French knight Lancelot becomes the main character, bringing French culture and honor to a backward, uncouth Camelot, and ultimately usurping the throne from the Brythonic King Arthur, while the Celtic hero Gawain is reduced to a jealous second fiddle. Thus the figure of Lancelot can be viewed as a bit of French cultural imperialism.