Oliver Cromwell with Sir Thomas Fairfax in command and Cromwell as Lieutenant-General of cavalry and second-in-command. At the critical Battle of Naseby in June 1645, the New Model Army smashed the King's major army. Cromwell led his wing with great success at Naseby, again routing the Royalist cavalry. At the Battle of Langport on 10 July, Cromwell participated in the defeat of the last sizeable Royalist field army. Naseby and Langport effectively ended the King's hopes of victory, and the subsequent Parliamentarian campaigns involved taking the remaining fortified Royalist positions in the west of England. In October 1645, Cromwell besieged and took
Prince Rupert of the Rhine led the relief of Newark and York and its castle. Having marched north, taking Bolton and Liverpool along the way in two bloody assaults, Rupert then intervened in Yorkshire in two highly effective manoeuvres, in the first outwitting the enemy forces at Newark with speed; in the second, striking across country and approaching York from the north. Rupert then commanded much of the royalist army at its defeat at Marston Moor, with much of the blame falling on the poor working relationship between Rupert and the Marquess of Newcastle, and orders from the King that wrongly conveyed a desperate need