Henry Mainwaring Henry Mainwaring Sir Henry Mainwaring (1587–1653), was an English lawyer, soldier, author, seaman and politician who sat in the House of Commons from 1621 to 1622. He was for a time a pirate based in Newfoundland and then a naval officer with the Royal Navy. He supported the Royalist cause in the English Civil War. Mainwaring was born in Ightfield, Shropshire, second son of Sir George Mainwaring and his wife Ann, the daughter of Sir William More of Loseley Park in Surrey. His maternal grandfather was Sir William More, Vice-Admiral of Sussex. He graduated from Brasenose College at Oxford University,
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