From A Wiki of Ice and Fire
Raymun, better known as Raymun Redbeard, was a King-Beyond-the-Wall. He is renowned for having led an invasion of the North in the time of Jon Snow's grandfather's grandfather.
Raymun united the free folk clans north of the Wall as King-Beyond-the-Wall. He had seen the Night's Watch decline and growing laxness and in 184AC took advantage of the situation. Sending his reavers over it after establishing a toehold for themselves on the Wall, they used thrown ramparts of their own and dropped ropes and ladders for his people to cross over. Because the Night's Watch was caught off guard as Redbeard's horde came down upon the North, its lord commander, Jack Musgood, was henceforth called Sleepy Jack.
Eventually Raymun's host met a bloody end on the shores of Long Lake, caught between Lord Willam Stark of Winterfell and the Drunken Giant, Lord Harmond Umber. During the fight, Willam was slain and his younger brother, Artos Stark, known as the Implacable, slew Raymun Redbeard. Raymun's brother fled from battle and was known after as the Red Raven. The Watch arrived too late to fight the wildlings but in time to bury them, the task that Artos assigned them in his wroth as he grieved above the headless corpse of his fallen brother Willam.
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