Cregan Stark

Cregan Stark is an unseen character in Game of Thrones. He is long dead by the time of the series. He was a Lord of Winterfell and an ancestor of House Stark.

Biography
Cregan Stark once fought with Aemon Targaryen the Dragonknight, member of the Kingsguard and one of the greatest swordsmen of his age, and was only barely defeated.

Season 4
His name is mentioned within the entry of Aemon Targaryen in the Book of Brothers.

In The Books
In the books, Cregan Stark's background is the same. Aemon Targaryen afterwards remarked that he never met a finer swordsman.