Arthur Haselrig was the eldest son of Sir Thomas Haselrig (also spelt "Heselrige", "Hazelrig", Haselrigge"), baronet, of Noseley in Leicestershire. He became a baronet and inherited extensive estates in the Midlands on the death of his father in 1630. Haselrig held radical political and religious views and was an outspoken critic of King Charles' Personal Rule. He was brought before the court of High Commission several times for non-payment of fees and taxes and was briefly imprisoned in the Tower of London. After his first wife died, he married Dorothy Greville, the sister of Lord Brooke, in 1634. Through Brooke, he came into contact with the network of Puritan critics of King Charles headed by Lord Saye and Sele.
Haselrig was elected one of the knights of the shire for Leicestershire in both the Short and Long Parliaments where he was associated with John Pym and the opponents of the King's government. He played a leading role in the impeachment of Lord Strafford and proposed the bill of attainder by which Strafford was condemned to death. Haselrig was also active in instigating the Root and Branch Bill, aimed at the abolition of bishops, and the Militia Bill. Regarded as one of the King's leading opponents, Haselrig was among the Five Members whom the King attempted to arrest in January 1642.
When the First Civil War broke out, Haselrig raised a regiment of horse which, unusually for the civil wars, he equipped as fully-armoured cuirassiers. Haselrig's regiment became known as the "Lobsters" and formed the heavy cavalry in the army of Sir William Waller. Haselrig fought with distinction at Lansdown in July 1643, but the Lobsters were routed at Roundway Down eight days later. Haselrig himself was wounded in both battles. In March 1644, Haselrig and his cuirassiers played a decisive role in the defeat of the Royalists at the battle of Cheriton. He supported Cromwell's criticism of the Earl of Manchester in November 1644 and when Parliament adopted the Self-Denying Ordinance he resigned his commission and became a leader of the Independent faction in the House of Commons.
Haselrig returned to military duties in December 1647 when he was appointed governor of the strategically-important city of Newcastle amid rumours that a Scottish army was being raised for the invasion of England. He retained control of Newcastle throughout the Second Civil War. In August 1648, Haselrig recaptured Tynemouth Castle from Henry Lilburne, who had defected to the Royalists. He went with Cromwell to Edinburgh in October 1648 and also accompanied him on the Dunbar campaign in 1650. After the victory at Dunbar, Haselrig was given charge of 5,000 Scottish prisoners who were forced to march 120 miles in eight days with little food from Dunbar through Berwick, Morpeth and Newcastle, to Durham. Around 1,500 prisoners died on the march.
As a convinced republican, Haselrig approved the overthrow of the monarchy, though he declined to sit as a judge at the King's trial. He became a leading figure in the Commonwealth and a member of the Council of State. Haselrig remained a powerful figure in Northumberland and Durham during the early 1650s and amassed a large fortune by dealing in sequestered Royalist estates and former church lands. He was often accused of corruption and of abusing his position for personal gain, notably by John Lilburne who claimed that Haselrig was a worse tyrant than the Earl of Strafford had been.
Haselrig broke with Cromwell after the expulsion of the Purged Parliament in April 1653. He vehemently opposed Cromwell's elevation to the office of Lord Protector in December 1653 and refused to pay taxes not sanctioned by Parliament. In 1654, he was elected MP for Leicestershire in the First Protectorate Parliament during which he emerged as one of the severest critics of the Protectorate government. He withdrew from Parliament after refusing to subscribe to the "Recognition" of the Protectorate insisted upon by Cromwell. In 1656, Haselrig was elected to the Second Protectorate Parliament but he was one of the members excluded from sitting in the first session by the Council of Officers. He refused Cromwell's offer of a seat in the new Upper House and was re-admitted to the Commons for the second session of parliament in January 1658. Haselrig was involved in the drafting of a petition calling for the abandonment of the Protectorate and the restoration of the Commonwealth that led Cromwell to dissolve Parliament in February 1658.
After Oliver's death in September 1658, Haselrig refused to support his successor Richard Cromwell. In the early sessions of the Third Protectorate Parliament, Haselrig attempted to delay discussion of the Act of Recognition of the new Protector in the hope that his authority would be compromised. When Richard was forced to recall the Purged Parliament in May 1659, Haselrig hoped to establish a civilian republican government. His uncompromising efforts to bring the Army under civilian control tended to alienate the military leaders from Parliament.
Haselrig unwittingly set in motion the train of events that led to the Restoration by calling for the impeachment of Colonel Lambert — with the result that Lambert threw an armed guard around the Palace of Westminster, ejected Parliament and dissolved the Council of State. Haselrig was one of nine members of the Council who refused to accept the dissolution and appealed to General Monck for support against Lambert and the military junta that had seized power. While Monck prepared to march south in December 1659, Haselrig went to secure the naval base at Portsmouth for Parliament where he was greeted warmly by the republican governor, Nathaniel Whelan. Forces sent by the junta to besiege Portsmouth were persuaded to join with the garrison and declare for Parliament. Haselrig returned to London at the end of December with three regiments to support the reinstatement of the Purged Parliament, which met again on 26 December. During the brief final revival of the republican Commonwealth, Haselrig was the unofficial leader of Parliament. He was re-appointed to the Council of State and to the army commission and believed that he had finally achieved his goal of a civilian-led republic in England.
Haselrig realised too late that General Monck intended to recall Charles Stuart and is said to have dropped his opposition to the Restoration when Monck promised that his own life would be spared. Nevertheless, Haselrig was imprisoned in the Tower of London in May 1660. He died in January 1661 before he could be brought to trial for treason.
References:
C.H. Firth, Sir Arthur Heselrige or Haselrig, DNB, 1891
Godfrey Davies, The Restoration of Charles II, 1658-60, 1955
Christopher Durston, Sir Arthur Hesilrige, Oxford DNB, 2004