Which knight is famous for his affair with Guinevere?

The knight famous for his affair with Guinevere is Lancelot.

Lancelot is Arthurian legend’s foremost knight and, in many medieval romances, Queen Guinevere’s forbidden lover. Their relationship begins in the French romance tradition, especially Chrétien de Troyes’s 12th-century poem *Lancelot, the Knight of the Cart*. Later prose cycles and Thomas Malory’s *Le Morte d’Arthur* make the affair a central thread of the legend.

Lancelot’s love for Guinevere conflicts with his loyalty to King Arthur and the ideals of chivalry. When their adultery is exposed, the scandal fractures the Round Table, contributes to civil war, and helps bring about Arthur’s downfall. Lancelot is also the father of Galahad, the exceptionally pure knight associated with the Holy Grail.

A common mix-up is Tristan, who is famous for his love of Isolde, not Guinevere. Galahad is chiefly linked to the Grail quest, while Gawain is Arthur’s celebrated nephew and a leading Round Table knight.