Cornwall in the English Civil War Cornwall played a significant role in the English Civil War , being a Royalist enclave in the generally Parliamentarian south - west . Civil War military actions in Cornwall and the South West . The English Civil War lasted nearly nine years , having begun with the battle of Edgehill , in Warwickshire , on Sunday , 23 October 1642 , and ended with the battle of Worcester , on 3 September 1651 . The principal events in Cornwall happened in the following order . 1642 . In 1642 Cornwall , Wales and the Marches were Royalist strongholds whilst South East England was held by Parliament , and the remainders of the country were in dispute . The Cornish - Royalist Army was formed by Ralph Hopton , 1st Baron Hopton in 1642 and although their first invasion of Devon in November – December 1642 ended in failure the army secured the Cornish side of Plymouth Sound which marked a serious reverse for Parliamentarian forces . 1643 . The Battle of Braddock Down . The Battle of Braddock Down near Boconnoc on 19 January 1643 resulted from a parliamentarian counter - invasion of Cornwall . It ended in defeat for Col . Ruthin ' s Parliamentarian troops by Sir Ralph Hopton . Hopton ' s victory secured Cornwall for the King and the Royalists resumed the siege of Plymouth with their forces occupying surrounding towns to seal off the city by land . The Battle of Stratton . The Battle of Stratton occurred on 15 May 1643 . The Earl of Stamford ' s Parliamentarian force was repelled by Hopton ' s men after day - long fighting , with 300 men killed and 1700 captured , and retreated to Bideford . The victories for Hopton with five ' Old Cornish ' regiments provided the impetus for campaigns in Devon and Somerset . Taunton and Bridgwater were taken by the Cornish army , but Sir Bevil Grenville was killed in the moment of victory at the Battle of Lansdown in Somerset and Hopton was seriously wounded . Bristol fell to Hopton ' s Royalist troops , followed by Exeter . On December 13 , the Royalists began a heavy bombardment of the northern defences of Plymouth but with little effect . Sir Richard Grenville , 1st Baronet , having previously declared for Parliament , invited his troops to follow him into the King ' s service and parliament proclaimed him a traitor . 1644 . Siege of Plymouth . Sir Richard Grenville arrived in Plymouth in March 1644 to maintain a blockade , but it resulted in a stalemate as the inhabitants obtained enough provisions to survive . Robert Devereux , 3rd Earl of Essex , arrived in command of the Roundhead army of 8000 men and forced Grenville to retreat to Cornwall across the River Tamar . The Battle of Lostwithiel . After relieving Plymouth , Essex advanced into Cornwall , reaching Bodmin on 28 July . King Charles meanwhile led the main Royalist army against him , blocking his line of retreat . Caught between Charles and Grenville , Essex took up positions at Lostwithiel and Fowey , hoping for support or evacuation by the Parliamentarian fleet . The Royalists cut off his escape routes by land and on 13 August Charles began his attack . On 21 August , the Royalists took Restormel Castle and Beacon Hill , Lostwithiel . After further sporadic fighting they pushed the Parliamentarians back to Castle Dore above the Fowey river on 31 August . That night the Parliamentarian cavalry broke through the encircling Royalists and escaped to Plymouth . On 1 September the Royalists took Castle Dore and Essex escaped by sea , leaving his 6000 infantry , artillery and baggage train under the command of Sir Philip Skippon , who surrendered the following day . The Royalists confiscated the Parliamentarians ' weapons and then allowed them to return to Portsmouth . Afflicted by bad weather , hunger , disease and attacks from local people , 1000 of the disarmed soldiers died along the way . Their time in Lostwithiel saw the vandalism of Lostwithiel Stannary Palace , Jonathan Rashleigh ' s Menabilly House , the destruction of all the constitutional Charters and Stannary records placed in Luxulyan church for safety . The ensuing debate in London about the unsatisfactory manner of the war led to the passage of the Self - Denying Ordinance . This was the prompt for a professional English army with a unified command , the New Model Army . 1645 . In 1645 Sir Thomas Fairfax was appointed the commander of the New Model Army . The Royalist army was also reorganised with Prince Charles becoming the Commander - in - Chief . The Royalists suffered a notable loss at Naseby in Northamptonshire and there were further Parliamentarian gains in the south and west of England . Prince Charles , the war being mainly in the eastern counties , spent a great part of the autumn and winter in Cornwall , principally at Launceston and Truro . Sir Richard Grenville was committed by the Prince to Launceston Prison , for refusing to obey Lord Hopton : he had already quarrelled with General George Goring . 1646 . In 1646 the Prince gave Lord Hopton command of the Royalist forces , with William Wentworth , 2nd Earl of Strafford to command the horse and Grenville the foot . Grenville refused and was imprisoned on St Michael ' s Mount . Hopton advanced from Stratton towards Exeter , reaching Torrington but was confronted by Fairfax ' s men , and fell back to Stratton . The Roundheads proceeded into Cornwall reaching Launceston on 25 February 1646 and Bodmin on 2 March . Hopton ' s army was in disarray but he refused to surrender . News at Bodmin of an imminent Irish invasion further damaged the Royalist cause locally and Fairfax offered Hopton terms . The surrender took place at Tresillian Bridge , Truro , on 15 March 1646 . 1648 . The Gear Rout . The Gear Rout was a Cornish insurrection of 1648 following the end of the First English Civil War . The killing of 70 Cornish Royalists in Penzance on 16 May 1648 prompted a failed rebellion by some 500 Cornish rebels who fought against the Parliamentarian forces of Sir Hardress Waller at a site near the Helford River .