Isabel of Cambridge, Countess of Essex was the only daughter of Richard, 3rd Earl of Cambridge and Anne Mortimer.
Background
Isabel of York, the only daughter of Richard of Conisburgh, 3rd Earl of Cambridge, and Lady Anne de Mortimer, was born about 1409. Through her father, she was the granddaughter of King Edward III"s fourth surviving son, Edmund of Langley, 1st Duke of York, and his first wife, Isabella of Castile. Her mother was the granddaughter of Roger Mortimer, 4th Earl of March (grandson of Lionel of Antwerp) and Lady Alianore Holland (granddaughter of Lady Joan of Kent, Princess of Wales).
Career
She was the sister of Richard Plantagenet, 3rd Duke of York, and like him a great-grandchild of Edward III of England. Isabel"s father, Richard, Earl of Cambridge, was beheaded on 5 August 1415 for his part in the Southampton Plot against King Henry V, and although the Earl"s title was forfeited, he was not attainted, and Isabel"s brother, Richard, then aged four, was his father"s heir. Henry Bourchier, 1st Earl of Essex, died on 4 April 1483.
Isabel remained a widow and died on 2 October 1484.
A manuscript calendar records her death on VI Non October in 1484. Both were buried at Beeleigh Abbey near Maldon, Essex, but later reburied at Little Easton, Essex.