Earl of Rosebery
He is the eldest surviving son of Harry, Earl of Rosebery. His paternal grandfather was Archibald Primrose, 5th Earl of Rosebery, the Liberal Prime Minister of the United Kingdom from 1894 to 1895. His paternal grandmother was the heiress Hannah, Countess of Rosebery (daughter of Mayer de Rothschild), who was regarded as the richest woman in England in the late 19th century.