Civil War
Haselrig was very active in the First English Civil War on the Parliamentarian side. He raised a troop of horse for the Earl of Essex and fought at the Battle of Edgehill. He was a commander in the West under William Waller, being nicknamed his fidus Achates, and led his cuirassiers, who were known as the London lobsters. He and his troops distinguished themselves at the Battle of Lansdowne on 5 July 1643, where his men defeated Sir Beville Grenville's Pikemen, although the battle is traditionally seen as indecisive. At the Battle of Roundway Down, on 13 July, Haselrig's force met a Royalist cavalry charge at the halt and after a brief clash, retreated in disorder, the Parliamentarian army losing the battle to Lord Wilmot. Haselrig was shot three times at Roundway Down, with the bullets apparently bouncing off his armour. After firing a pistol at Haselrig's helmeted head at close range without any effect Richard Atkyns described how he attacked him with his sword, but it too caused no visible damage; Haselrig was under attack from several people and succumbed only when Atkyns attacked his unarmoured horse. After the death of his horse Haselrig tried to surrender, but as he fumbled with his sword, which was tied to his wrist, he was rescued. He suffered only minor wounds from his ordeal. This incident was related to Charles I and elicited one of his rare attempts at humour. The king said that if Haselrig had been as well supplied as he was fortified he could have withstood a siege.
At the Battle of Cheriton, his men defeated Sir Henry Bard's cavalry charge, seriously weakening Ralph Hopton's army in the west. This battle was a turning point in the war and the king's secretary Sir Edward Walker said that after Cheriton, instead of an offensive war they were forced to make a defensive war.
