John Mordaunt, 1st Viscount Mordaunt, 1626-75

Royalist conspirator involved in several plots against the Commonwealth and Protectorate governments.

Portrait of John MordauntJohn Mordaunt was born at Lowick in Northamptonshire. He was the second son of the fifth Baron Mordaunt (also called John Mordaunt), who became first Earl of Peterborough in 1628, and of Elizabeth, daughter of Lord Howard of Effingham. Although his mother was Presbyterian, the Mordaunt family had been prominent Northamptonshire Roman Catholics. John Mordaunt's grandfather, the fourth Baron Mordaunt, had been implicated in the Gunpowder Plot.

Mordaunt was educated privately in France and Italy and was probably still abroad on the outbreak of civil war in 1642. His father, the Earl of Peterborough, supported Parliament and commanded an infantry regiment and artillery train. Upon his death in June 1643, he was succeeded as second Earl of Peterborough by Henry Mordaunt (1623-97), John's elder brother, who defected to the Royalists. Henry led a distinguished military career in the King's service throughout the First Civil War. In 1648, John joined Henry to participate in the Royalist insurrection in Surrey led by the Earl of Holland. Both brothers escaped to The Hague after the failure of the uprising.

In 1654, Sir Edward Hyde accepted Mordaunt's offer of service to the Royalist cause. He returned to England in 1656 and became involved in conspiracies against Cromwell's Protectorate. His mother's connections qualified Mordaunt to act as an intemediary between the Presbyterians and the Royalists. Rejecting the cautious approach of the conspirators of the Sealed Knot, Mordaunt emerged as a leading member of the militant New Action Party, which plotted to foment an uprising against the government in support of a projected invasion by a Spanish army.

Early in 1658, Mordaunt collaborated with the Marquis of Ormond on a secret visit to London to co-ordinate Royalist conspirators in England. However, Cromwell's agents learned of Ormond's presence and he was forced to escape to the Continent in February 1658. Mordaunt was arrested in April following his betrayal by a Royalist turncoat, John Stapley. After being questioned by Cromwell himself, Mordaunt was released from custody, only to be re-arrested two weeks later and charged with treason. He was brought to trial along with Dr John Hewitt and Sir Henry Slingsby before a specially reconvened High Court of Justice in June 1658. Hewitt and Slingsby were both condemned to death but the Court was equally divided over Mordaunt's case; he was acquitted by the casting vote of the lord-president John Lisle.

On Hyde's recommendation, Charles II appointed Mordaunt to the Great Trust and Commission, a secret organisation charged with fomenting a Royalist-Presbyterian uprising to bring about the Restoration after the death of Oliver Cromwell in September 1658. As a mark of favour, Charles created him first Viscount Mordaunt of Avalon in March 1659, but bitter divisions and a lack of co-operation between Mordaunt and his colleagues of the Sealed Knot thwarted and delayed plans for the uprising. The general insurrection planned for August 1659 was sporadic, and only Booth's Uprising in Cheshire achieved even partial success. Mordaunt declared for the King at Barnstead Down in Surrey, but only thirty men supported him. He narrowly avoided capture and escaped to the Continent in September 1659.

Although Mordaunt continued to work tirelessly for the Royalist cause, his prestige was damaged by the failure of the 1659 uprising and he lost favour with the King. He urged an alliance with France and warned against trusting General Monck, being initially unaware of Sir John Grenville's secret negotiations with Monck on the King's behalf early in 1660. However, Mordaunt's services were rewarded at the Restoration: he was knighted in May 1660 and appointed lord-lieutenant of Surrey and governor of Windsor Castle.

Mordaunt's abrasive personality hindered his advancement at the Restoration court and gained him many enemies. In 1666, he was impeached by Parliament over an accusation that he had unlawfully imprisoned the surveyor of Windsor Castle and raped his daughter. The case never came before the House of Lords because the King prorogued Parliament in February 1667 and pardoned Mordaunt in July, though Mordaunt became extremely unpopular. After the fall from power of his patron Sir Edward Hyde, Earl of Clarendon, Mordaunt resigned his public offices and retired to France until 1669. Thereafter he lived quietly at Parson's Green in Middlesex, where he died in June 1675.

Mordaunt married Elizabeth Carey in May 1657. They had eleven children, the eldest of whom, Charles Mordaunt, became third Earl of Peterborough and was a noted general during the War of the Spanish Succession (1701-14).


Godfrey Davies, The Restoration of Charles II, 1658-60, 1955

Victor Stater, John Mordaunt, 1st Viscount Mordaunt of Avalon, Oxford DNB, 2004

Victor Stater, Henry Mordaunt, 2nd Earl of Peterborough, Oxford DNB, 2004

David Underdown, Royalist Conspiracy in England 1649-60 (New Haven 1960)


Mordaunt Family History and Genealogy Resource