January 9, 1769, Althorp House, Northampton, Northamptonshire, England.
October 23, 1834, Paris, France.
Harrow School Chapel, Harrow on the Hill, London, England.
William was the younger son of Lord Charles Spencer and his wife Mary Beauclerk. He was the grandson of Charles Spencer, 3rd Duke of Marlborough on his father’s side and Vere Beauclerk, 1st Baron Vere on his mother’s. Spencer was educated at Harrow School and Christ Church, Oxford, though he left Christ Church without receiving a degree.