Launcelot is Arthur's best knight and is totally devoted to Queen Gwenyvere.
In his first adventure in LeMorte, he rescues some of Arthur's knights from the dungeon of Sir Tarquin.
Launcelot fathers a child, Galahad, with Elayne of Corbin when he gets tricked into thinking she's Gwenyvere.
Launcelot goes crazy when Gwenyvere rebukes him for sleeping with Elayne, and runs wild in the forest for many months.
Launcelot's wits return when Elayne finds him and has him carried before the Holy Grail.
After he spends some time living with Elayne and Galahad near Corbin, Launcelot returns to court when he finds out how much Gwenyvere misses him.
Gwenyvere exiles Launcelot from court again when she becomes jealous that he fights for so many different women (although this is just to throw the other knights off the scent of his and Gwenyvere's affair).
Nevertheless, Launcelot returns to court to serve as Gwenyvere's champion when she gets accused of poisoning one of Arthur's knights.
Launcelot rides incognito to a tournament and, along the way, meets Elayne of Ascolat, who nurses him back to health after he's wounded.
Unfortunately, out of devotion to Gwenyvere, Launcelot rejects Elayne's marriage proposal, causing her to die of grief.
Launcelot rides to the castle of Sir Mellyagaunce to rescue Gwenyvere.
While there overnight, Launcelot bloodies Gwenyvere's bed, enabling Mellyagaunce to accuse her of sleeping with another one of Arthur's knights.
Launcelot defeats Mellyagaunce in the battle to disprove this accusation.
Later, back at court, Mordred and Aggravayne catch Launcelot in the Queen's bed-chamber.
Launcelot rescues Gwenyvere from being burned at the stake when she's accused of having an affair with him, then returns her to Arthur at the request of the Pope.
To avoid battle with Arthur, Launcelot travels to France with his loyal knights, and makes them his vassals.
Launcelot defends his lands against Arthur's eventual invasion, and fights one-on-one with Gawain.
After Arthur and Gawain die, Launcelot travels to England and finds Gwenyvere in a convent.
So Launcelot becomes a monk and priest. He buries Gwenyvere's body next to Arthur's.