After Stannis Baratheon raised the siege of the Wall and threw back Mance Rayder's wildlings, he turned south to press his claim as King of Westeros by winning the north to his cause. He retook Deepwood Motte from the ironborn, drawing to his banners the mountain clans and such northern houses as still remembered their oaths to Winterfell, and then set out overland to break the power of House Bolton, whom the Iron Throne had named Wardens of the North after the treachery of the Red Wedding. His march became a battle against the land itself, for an early and savage winter fell upon his host as it crossed the snows, miring the column, killing his horses, and starving his men within sight of their goal at a village three days from Winterfell, where the army made its camp upon the shore of a great frozen lake.
Against Stannis stood Lord Roose Bolton, holding Winterfell with a host of Bolton, Frey, Manderly, and other northern spears far larger than the king's own. The maesters record that Stannis marched under a hidden blade of his own, for Arnolf Karstark, castellan of Karhold, had brought his strength into the royal host while secretly conspiring to betray his king to the Boltons at the hour of battle, a plot uncovered before it could be sprung. The engagement takes its name from the frozen lake beside which it was to be fought, its ice a treacherous ground for the massed cavalry the Boltons and Freys could bring to bear.
It must be set down plainly that the Battle of Ice remains unresolved and has not yet occurred in the published novels. The armies stand poised, Stannis camped upon the lake in the teeth of the blizzard and Roose Bolton secure behind the walls of Winterfell, but the clash itself lies beyond the close of the histories set down so far, and its victor, its dead, and its consequences for the war in the north are not yet known.