[1] Through her mother, she was a granddaughter of John of Gaunt[2] and a great-granddaughter of King Edward III.
On 12 January 1412, Katherine was married at the age of 15 to John Mowbray, 2nd Duke of Norfolk (1392–1432).
Chronicler William Worcester referred to the match as being rotting revenge for both parties "vindicta Bernardi inter cosdem postem putrit".
Nonetheless, she survived him, as he was executed in 1469 after the Battle of Edgecote, on the orders of her nephew Richard Neville, 16th Earl of Warwick, during a Lancastrian rebellion against Edward IV.
Whether or not she was forced into her final marriage against her will is unclear, but the unsavoury details added to the deep dislike of the Queen's family among the ruling class, which greatly weakened the Yorkist dynasty.