- "A hundred years ago, another King-Beyond-the-Wall, Raymun Redbeard, realized the Wall's size is both its greatest strength and its greatest weakness. He waited for our patrols to pass and sent climbers to the now unguarded stretch of the Wall. When they reached the top, they dropped ropes and ladders for thousands more wildlings to clamber up. The Night's Watch didn't even know his army had crossed until after the Starks and Umbers had cornered and destroyed him, and that was a hundred years ago, when the Watch had many more men than now."
- ―Samwell Tarly
Raymun Redbeard assumed the title of King-Beyond-the-Wall and led an invasion of the North. He figured that the Wall's massive size was both its greatest advantage and its greatest flaw, making it impossible to patrol the entire fortification day and night. So when the patrols passed, he sent his climbers to scale the Wall and leave ropes and ladders for his army to follow after.
In the books
In the A Song of Ice and Fire novels, Raymun Redbeard was King-Beyond-the-Wall in the time of Lord William Stark, the grandfather of Lord Rickard Stark. Having seen the decline of the Night's Watch under the leadership of Lord Commander Jack Musgood, Raymun and his raiders crossed over the Wall and invaded the North. Eventually, the invading force engaged in battle against the Northerners led by William Stark and Lord Harmond of House Umber, "the Drunken Giant". Lord William was slain and his younger brother, Artos Stark, "the Implacable", slew Raymun. Raymun's younger brother fled back beyond the Wall and became known as "the Red Raven", for having fled from battle, "Red" for the color of his hair and "Raven" because it rhymed with "craven".
The Night's Watch arrived too late to fight so Artos, grieving over the headless corpse of his brother, assigned them the shameful task of burying the dead. Lord Commander Musgood was forever after known as "Sleepy Jack".
The wildling raider Gerrick Kingsblood boasts direct descent from Raymun Redbeard but is actually descended from the Red Raven, a fact most Free Folk are aware of and use to disparage him.
The Tales of Dunk and Egg prequel novellas begin in 209 AC, and while the three currently published ones only extend to the year 211 AC, future installments are intended to stretch forward to over the next fifty years of history, using time jumps. Raymund Redbeard led his attack over the Wall in 226 AC, meaning that he is the current King-Beyond-The-Wall during the Tales of Dunk and Egg era, and that he might appear in any potential live-action adaptation of the prequels.