A moratorium is in effect on adding information from Fire and Blood until December 20th.
The Barrow Kings claimed descent from the First King of the First Men, who is said to be buried at Great Barrow at Barrowton. Some Barrow Kings allied with Marsh Kings against southron invaders who tried to pass the Neck.
Singers claim the Barrow Kings fought against the Kings of Winter, the Starks of Winterfell, north of the barrowlands, in the Thousand Years War, but runes of the First Men indicates the conflict lasted about two hundred years. When the last Barrow King submitted to Winterfell, the Stark king received his daughter in marriage. The Dustins of Barrowton claim descent from the First King and the Barrow Kings.
Maester Kennet's Passages of the Dead mentions a curse was supposedly placed on the Great Barrow, weakening and making corpselike any living man who dared to equal the First King. Some maesters think the corpse queen of the Night's King may have actually been a daughter of a Barrow King, as they were often connected with graves.