The Battle of Naseby took place on June 14, 1645, during the English Civil War. It was a decisive confrontation between the forces of the Parliament, known as the New Model Army, and the Royalist troops loyal to King Charles I. The battle marked a turning point in the war, leading to a significant decline in Royalist power. The Parliamentarian victory at Naseby was largely due to superior tactics and organization. The battle resulted in heavy losses for the Royalists, with many soldiers killed or captured. This defeat ultimately contributed to the eventual downfall of the monarchy and the establishment of the Commonwealth under Oliver Cromwell.