Sir Robert Harley was an English statesman who served as Master of the Mint for Charles I. A devout Puritan, he supported Parliament in the Wars of the Three Kingdoms.

Earl of Oxford and Earl Mortimer was a title in the Peerage of Great Britain. It was created in 1711 for the statesman Robert Harley, with remainder, failing heirs male of his body, to those of his grandfather, Sir Robert Harley. He was made Baron Harley, of Wigmore in the County of Hereford, at the same time, also in the Peerage of Great Britain and with similar remainder as for the earldom. Harley was the eldest son of Sir Edward Harley and the grandson of the aforementioned Sir Robert Harley.