First Civil War 1642-1646
Taking Sides: Royalists and Parliamentarians
When Charles I raised his standard at Nottingham in August 1642, neither side expected a long war. The King’s supporters — often called Cavaliers by their opponents — and Parliament’s supporters — often called Roundheads by theirs — were largely drawn from the same social world. Both labels were partisan insults at the time, not neutral descriptions. Support divided roughly along religious and economic lines: the north and west tended Royalist; London, the south-east and the navy backed Parliament.
England’s civil wars (1642–1651) killed an estimated 85,000 in combat, and about 100,000 more died of war-related disease — perhaps 4% of England’s population. The non-combat toll is often overlooked.
Edgehill and the Early War 1642–1643
The first major engagement at Edgehill on 23 October 1642 was inconclusive. Prince Rupert’s Royalist cavalry routed the Parliamentarian horse but then rode off the field in pursuit, allowing the Parliamentarian infantry to hold their ground. Neither side could deliver a decisive blow. Charles marched on London but was checked at Turnham Green in November 1642, when a large trained-band force blocked his advance. He retreated to Oxford, which became his wartime capital.
Through 1643 the Royalists gained ground in the north and west. However, Parliament secured a vital alliance: the Solemn League and Covenant (September 1643) brought the Scottish Covenanting army into the war on Parliament’s side in exchange for a promise to establish Presbyterianism in England. This commitment would prove politically explosive later.
The Battle of Marston Moor (2 July 1644) was the largest battle of the Civil War, involving around 45,000 men. The combined Parliamentary and Scottish army crushed the Royalists under Prince Rupert and the Marquess of Newcastle. The north of England fell permanently to Parliament. It was also the battle that established Oliver Cromwell’s military reputation. His disciplined cavalry — nicknamed the “Ironsides” after Prince Rupert called Cromwell “Old Ironsides” — fought effectively and returned after the charge rather than pursuing, unlike most cavalry of the period.
The New Model Army and the Self-Denying Ordinance
Despite Marston Moor, Parliament failed to win quickly. Part of the problem was military leadership: the Earl of Essex and the Earl of Manchester commanded the main armies but proved reluctant to press their advantages. Cromwell criticised Manchester openly, and in April 1645 Parliament passed the Self-Denying Ordinance. Under this, MPs and lords had to give up their military commands — removing Essex and Manchester.
In April 1645 Parliament established the New Model Army. Its commander was Sir Thomas Fairfax, with Cromwell (who was given an exemption from the Self-Denying Ordinance) as Lieutenant-General of Horse. The New Model was a paid, professional force with a unified command. It was also unusual in religion — officers and soldiers read their Bibles and argued theology alongside fighting.
The New Model Army, commanded by Sir Thomas Fairfax with Cromwell as cavalry commander, was a unified national force — unlike earlier regional armies. Its discipline and religious motivation gave Parliament the military edge it had lacked.
Naseby and the End of the First Civil War
The Battle of Naseby on 14 June 1645 effectively ended the First Civil War. Fairfax and Cromwell’s New Model Army met Charles and Prince Rupert at Naseby in Northamptonshire. The Royalist cavalry again broke the Parliamentary horse on one wing, but Cromwell’s disciplined cavalry held on the other, routed the Royalists, and then turned on the Royalist infantry. Approximately 5,000 Royalist foot soldiers were captured. Critically, Charles’s private correspondence was also captured, showing he had been negotiating with Irish Catholics and foreign powers — deeply damaging to his reputation.
Charles surrendered to the Scottish army in May 1646, who handed him over to Parliament in January 1647 after he refused to accept Presbyterianism. Parliament now controlled England. But the question of what to do with a defeated king — and who would govern — remained entirely unresolved.
In July 1646 Parliament sent Charles the Propositions of Newcastle, demanding he accept Presbyterianism and surrender control of the army for twenty years. Charles refused. He had no intention of accepting permanent subjugation — he was playing for time, hoping to split Parliament from its Scottish and army allies. His refusal to negotiate in good faith stored up the crisis of 1647–1649. The gap between his public statements of goodwill and private plotting remained a central feature of his kingship throughout.