|Title||Lord of Barrowton|
|Died||In 283 AC, at the Tower of Joy|
|Spouse||Lady Barbrey Ryswell|
|Book(s)|| A Game of Thrones (mentioned)|
A Feast for Crows (mentioned)
A Dance with Dragons (mentioned)
Upon the outbreak of Robert's Rebellion, Lady Barbrey gave the pride of her father's horse herds, a fine red stallion, to her husband when he traveled south with Lord Eddard Stark; Willam vowed he would return to her mounted on the fine steed.
Willam was one of Eddard's six companions the day he faced down three members of the Kingsguard at the Tower of Joy in the Red Mountains of Dorne, who were preventing Eddard from taking his sister Lyanna back. A fight broke out and though all three Kingsguard were killed, only Eddard and Howland Reed survived. Willam was buried by Eddard in a cairn in Dorne.
William's steed survived, however, and Eddard returned the horse to Willam's widow, Barbrey.
A Dance with Dragons
Barbrey Dustin, the widow of Willam and the Lady of Barrowton, reveals to Theon Greyjoy she still resents that Eddard Stark did not bring Willam back from Dorne, only his red stallion. If Eddard's bones are discovered, she will prevent them from being laid to rest in the crypt of Winterfell.