Lord of the Rills
The Ryders were First Men kings after the Long Night who were eventually defeated and reduced to vassals by the Kings of Winter, House Stark of Winterfell. House Ryswell ruled the Rills after them.
When the youngest son of a Lord Ryswell deserted the Night's Watch along with others black brothers, they rode to the Rills hoping his father would help them. Instead, Lord Ryswell sent them back to the Nightfort where the Lord Commander had holes hewn in the top of the Wall and he put the deserters in them and sealed them up alive in the ice. They are forever known as the Seventy-nine sentinels. When he was old and dying, Lord Ryswell joined his son.
A Feast for Crows
House Ryswell is one of the first houses to swear allegiance to Lord Roose Bolton of the Dreadfort after he is named the new Warden of the North by the Iron Throne. The Ryswells join his son, Ramsay Bolton, for the siege of Moat Cailin.