Henry Mainwaring in the King's cause in the English Civil War, was exiled to France, and died in poverty. He was buried at St. Giles' Church, Camberwell, London, on 15 May 1653. Mainwaring married a daughter of Sir Thomas Gardiner in 1630. She died in 1633. His brothers were Sir Arthur Mainwaring, Carver to Prince Henry, George Mainwaring, the defender of Tong Castle, and Sir Thomas Mainwaring, the Recorder of Reading. The Mainwaring family was old and distinguished, probably having arrived in England in the train of William the Conqueror (1066). Henry Mainwaring Sir Henry Mainwaring (1587–1653), was an English lawyer, soldier,
Henry Mainwaring of Pirates", on the suppression of piracy, 1618), the manuscript of which is in the British Museum. In his book, he explains what causes a desperate man to turn to piracy. He also advises the King against granting pardons to pirates. The King promptly dispatched Mainwaring to the Venetian Republic as his representative, over the protests of the Spanish ambassador. Mainwaring was knighted at Woking on 20 March 1618. He was commissioned in the Royal Navy. In 1621, he was elected Member of Parliament from Dover. Mainwaring became vice-admiral before leaving the navy in 1639. As a Royalist, he served