(Canto 5, line 128)
Lancelot, the son of a Breton king, was carried off while still a child by "the Lady of the Lake", who raises him. He is therefore known as Lancelot du Lac ("of the lake"). After he had grown up, the Lady sent him to king Arthur, where he became one of the Knights around his Table. His secret love for Arthur's queen Guinevere is what is referred to in this line.