メルバーン子爵
Cowper was the eldest son of Peter Clavering-Cowper, 5th Earl Cowper, and his wife Emily Lamb, daughter of Peniston Lamb, 1st Viscount Melbourne, sister of Prime Minister William Lamb, 2nd Viscount Melbourne, and a leading figure in Regency society. William Cowper-Temple, 1st Baron Mount Temple, was his younger brother. His mother married as her second husband the future Prime Minister Henry Temple, 3rd Viscount Palmerston, in 1839.