The Lady Margaret Gascoigne (née Percy) (born c. 1447) was an English noblewoman, the daughter of Henry Percy, 3rd Earl of Northumberland and Eleanor Poynings.
She married Sir William Gascoigne, "the Younger", son of Sir William Gascoigne and wife. Their daughter Agnes (or Anne) Gascoigne married Sir Thomas Fairfax (died 1520–1521), who was an ancestor of Catherine, Duchess of Cambridge. Lady Margaret Percy was a descendant of Edward III.
More information on the Wikipedia page [1].