Original: Prince Edward , Duke of York ( Edward Augustus ; 25 March 1739 -- 17 September 1767 ) , was the younger brother of George III of the United Kingdom , the second son of Frederick , Prince of Wales and Augusta of Saxe-Gotha .
Simplified: Prince Edward , Duke of York ( Edward Augustus ) lived from 1739 to 1767 . He was the youngest brother of George III of the United Kingdom .