His great-uncle, after whom he was named, was the Whig Lord Chancellor of Anne and George I.

His grandfather was that Spencer Cowper, judge of the Common Pleas, for love of whom the pretty Quakeress drowned herself, and who, by the rancour of party, was indicted for her murder.

His father, the Rev.

John Cowper, D.D., was chaplain to George II.

His mother was a Donne, of the race of the poet, and descended by several lines from Henry III.