The Battle of Naseby took place on Saturday 14 June 1645 during the First English Civil War, near the village of Naseby in Northamptonshire. The Parliamentarian New Model Army, commanded by Sir Thomas Fairfax and Oliver Cromwell, destroyed the main Royalist army under Charles I and Prince Rupert. Defeat ended any real hope of Royalist victory, although Charles did not finally surrender until May 1646.

The 1645 campaign began in April when the newly formed New Model Army marched west to relieve Taunton, before being ordered back to lay siege to Oxford, the Royalist wartime capital. On 31 May, the Royalists stormed Leicester and Fairfax was instructed to abandon the siege and engage them. Although heavily outnumbered, Charles decided to stand and fight and after several hours of combat his force was effectively destroyed. The Royalists suffered over 1,000 casualties, with over 4,500 of their infantry captured and paraded through the streets of London; they would never again field an army of comparable quality.

They also lost all their artillery and stores, along with Charles' personal baggage and private papers, which revealed his attempts to bring the Irish Catholic Confederation and foreign mercenaries into the war. These were published in a pamphlet titled The King's Cabinet Opened, whose appearance was a great boost to the cause of Parliament.



The English Civil War (1642–1651) was a series of civil wars and political machinations between Parliamentarians ("Roundheads") and Royalists ("Cavaliers"), mainly over the manner of England's governance and issues of religious freedom. It was part of the wider Wars of the Three Kingdoms. The first (1642–1646) and second (1648–1649) wars pitted the supporters of King Charles I against the supporters of the Long Parliament, while the third (1649–1651) saw fighting between supporters of King Charles II and supporters of the Rump Parliament. The wars also involved the Scottish Covenanters and Irish Confederates. The war ended with Parliamentarian victory at the Battle of Worcester on 3 September 1651.

Unlike other civil wars in England, which were mainly fought over who should rule, these conflicts were also concerned with how the three Kingdoms of England, Scotland and Ireland should be governed. The outcome was threefold: the trial and the execution of Charles I (1649); the exile of his son, Charles II (1651); and the replacement of English monarchy with the Commonwealth of England, which from 1653 (as the Commonwealth of England, Scotland, and Ireland) unified the British Isles under the personal rule of Oliver Cromwell (1653–1658) and briefly his son Richard (1658–1659). In England, the monopoly of the Church of England on Christian worship was ended, and in Ireland, the victors consolidated the established Protestant Ascendancy. Constitutionally, the outcome of the wars established the precedent that an English monarch cannot govern without Parliament's consent, though the idea of Parliamentary sovereignty was legally established only as part of the Glorious Revolution in 1688.