Lancelot was the son of King Ban of Benwick (Benoic) and Queen Elaine. This is possibly Guenet in Brittany. He was christened with the name Galahad, but was given the confirmation name of Lancelot.
His father was driven from his kingdom, either by a revolt of his subjects, caused by his own harshness, or by the action of his enemy Claudas de la Deserte. King and queen have to flee, carrying the child Lancelot with them, and while his mother is tending his father, who is dying of a broken heart, the infant is carried off by a friendly water-fay, the Lady of the Lake, who brings the boy up in her mysterious kingdom.
In the German poem this is an “Isle of Maidens,” where no man ever enters, and where it is perpetual spring. In the prose Lancelot, on the other hand, the Lake is a mirage, and the Lady's court has gallant knights; and the boy has the companionship of his cousins, Lionel and Bors (sons of his father's younger brother Bors), who, like himself, have been driven from their kingdom by Claudas.
When he reaches the age of manhood (fifteen or eighteen by different texts), the young Lancelot is sent out into the world. His real name and parentage are unknown to him. He rides out in search of what adventure he can find. In the prose Lancelot he goes with an Arthur's court where the Lady of the Lake asks that he be knighted.
He is known as Lancelot of the Lake or Lancelot du Lac because he was raised by the Lady of the Lake.