On 23 May 1711 the minister became Baron Harley, of Wigmore in the County of Hereford, and Earl of Oxford and Earl Mortimer (the latter, despite its form, being a single peerage). Harley claimed the title of Oxford because of his relationship through marriage to the previous holders, the De Veres. The title of Earl Mortimer was added in case a claim was laid to the Oxford earldom. On 29 May he was appointed Lord Treasurer, and on 25 October 1712 became a Knight of the Garter.