Earl Cadogan is a title that has been created twice in the Peerage of Great Britain. The Cadogan family descends from Major William Cadogan, a cavalry officer in Oliver Cromwell's army. His son Henry Cadogan was a barrister in Dublin. His eldest son William Cadogan was a noted soldier, politician and diplomat. He was a General in the Army and fought in the War of the Spanish Succession and also served as Ambassador to the Netherlands and as Master-General of the Ordnance. In 1716, he was raised to the Peerage of Great Britain as Baron Cadogan, of Reading in the County of Berkshire, with normal remainder to the heirs male of his body. In 1718, he was further honoured when he was made Baron Cadogan, of Oakley in the County of Buckingham, with remainder, failing heirs male of his own, to his younger brother Charles Cadogan and the heirs male of his body, and Viscount Caversham, in the County of Oxford, and Earl Cadogan, in the County of Denbigh, with remainder to the heirs male of his body. These titles were also in the Peerage of Great Britain.