Lot first rides into written history with Geoffrey of Monmouth, the twelfth-century cleric whose chronicle of British kings made Arthur famous across Europe. Geoffrey calls him Loth, king of Lothian, and marries him to Anna, the sister of Arthur, while Arthur is still a young conqueror. The northern connection runs deeper still: Geoffrey makes Lot the nephew and heir of the king of Norway, and later tradition gives him the stormy Orkney Islands, the scatter of rocks off Scotland's northern tip, as his seat. The very land remembers him, for the Lowlands around Edinburgh - Lothian - were said to carry his name. In the old Welsh genealogies he appears as Lleu ap Cynfarch, a lord of the heroic north, one of the men of the old British kingdoms that the Saxon tide was swallowing. From the beginning, then, Lot belongs to the north: to cold seas, border wars, and a pride that matched any crown in Britain.

His family is his monument. His wife, called Morgause in the later romances, is one of the three daughters of the Duke of Cornwall and the Duchess Igraine, and so a half-sister to Arthur, whom Igraine bore to King Uther Pendragon. To Lot and Morgause are born the sons who will dominate the Arthurian world: Gawain, in whom the sun's rising strength is said to live; Agravain, called the Proud; Gaheris; and Gareth, the youngest and most beloved, who wins his spurs disguised as a kitchen boy. But the darkest thread in the family weave is Mordred. In Geoffrey's telling Mordred is Lot's son outright, Arthur's nephew and trusted regent. In Malory's English version the truth is crueller: Morgause visits the young king's court, and Arthur, not knowing she is his half-sister, begets Mordred upon her. Lot raises the boy as his own, never knowing - or never saying - that the fifth son of his house carries the blood of the king and the doom of the kingdom.

Lot's own story is a rebel's arc. When the boy Arthur is crowned, Lot heads the alliance of eleven kings who scorn his birth and refuse him homage, and for years the wars roll across Britain: the great battle at Bedegraine, where Arthur first proves his sword; midnight plots in ravaged castles; truces sworn and broken. Yet the rebels are slowly won by the thing they doubted - Arthur's quality - and Lot kneels at last, becoming one of the king's staunchest allies. It is in those same wars that his fate is sealed. At the height of one battle, in Malory's telling, the knight King Pellinore, a hunter of monsters and one of Arthur's own champions, strikes King Lot through the helm in the press, and the northern king falls dead among his men.

That single sword-stroke opens a wound that never closes. The sons of Lot swear vengeance on the house of Pellinore, and Pellinore's sons answer in kind. Over the following years the feud claims Pellinore himself, ambushed and slain, and then his son Lamorak, one of the three best knights in the world, hacked down by Gawain's brothers in a quarrel over blood and a queen's bed. Gareth and Gaheris, who hold themselves apart from the vengeance, die instead by Lancelot's unknowing hand in the rescue of Guinevere, and that grief splits the Round Table beyond repair. When Mordred at last raises his banner against Arthur, the wreckage of Lot's house is complete: father dead by feud, mother disgraced, brothers slain by brothers' friends, and the last son standing over the king's corpse at Camlann.