Lancelot - The Love of Guenevere and Lancelot
In some versions of the legend, one of Lancelot's first tasks as a knight was to fetch Arthur's bride, Guenevere, to Camelot for their wedding. During this journey, Guenevere and Lancelot fell in love. In other stories, Guenevere was already established at court when Lancelot arrived, and he soon became one of the Queen's Knights, a sub-order of the Round Table of which young, aspiring knights belonged before they had fully proven themselves. Lancelot quickly established himself as the greatest knight of all time after successfully completing several quests.
During this period Lancelot won La Dolorous Garde, which became his own castle of Joyous Garde. Here the court joined him for a time, and Dagonet found him one day allowing his horse to wander wherever it would while he gazed in a fond trance at Guenevere. Leaving Joyous Garde, he became the prisoner of the Lady of Malohaut, who held him for the death of her seneschal's son, but allowed him to leave on parole to fight in tournament and fell in love with him when he returned. During this period he also conquered Duke Galeholt, winning the Duke's allegiance for Arthur and his friendship for Lancelot himself.
Meanwhile, Viviane had been softening Guenevere, and when next Lancelot joined the court for a time, he and Guenevere declared their love, with Galeholt and the Lady of Malohaut for go-betweens. This time, when Lancelot left again, he inspired perhaps the first of what was to become a standard activity - a party of Arthur's knights, including Gawaine and Kay, went out searching for him.
After joining the ranks of Knights of the Round Table, Lancelot helped Arthur put down the rebellion of Galeholt the Haut Prince, who surrendered to Arthur after observing Lancelot's chivalry and prowess in battle. Afterwards, Galeholt became Lancelot's closest friend and acted as a secret go-between Lancelot and Guenevere. The pair also took refuge in Galehaut's kingdom of Sorelois when Guinevere the False (Genievre) took the queen's place at court. After the deception was discovered, Lancelot restored the queen to Arthur, but by this time Lancelot and Guinevere were irrevocably in love.
The love of Lancelot and Guenevere is more fully described under Guenevere. Genievre's second, and temporarily successful, attempt to supplant Guenevere followed sometime after the defeat of Camille, and after literally saving Guenevere's skin, Lancelot retired with her to Galeholt's kingdom of Sorelois. They only returned to their places at court - Guenevere to her throne, Lancelot to his seat at the Round Table - after Genievre's death, while Galeholt let them go despite a prophecy that he could prolong his own life by keeping Lancelot with him.