Marston Moor was the first truly decisive battle of the English Civil War, and a major Parliamentary victory. By the end of the day, the Royalists had suffered 4,500 casualties and the north of England was in Parliamentary hands. It was also the first occasion on which Oliver Cromwell decisively influenced events at a national level.
Despite the setback at Marston, the news from Scotland and the west country during 1644-45 was more promising. The Highland Dimension offered Charles considerable grounds for optimism during this mid phase of the war. In what became known as the 'Year of Miracles', the Marquis of Montrose inflicted defeat after defeat on the Covenanters, led by Archibald Campbell, Duke of Argyll.
Royalist successes in Scotland and the west filled Charles with optimism. When Cavalier and Roundhead forces clashed at Newbury in October 1644, the Earl of Manchester's inertia allowed the Royalist army to escape intact. Shortly after the battle, Charles rubbed salt in Manchester's wounds by returning to collect arms and supplies and relieve Donnington Castle.
Manchester's vacillation created crisis in the Parliamentary ranks. Having taken the field to secure certain political and religious objectives, the senior Parliamentary commanders - Essex and Manchester - seemed strangely reluctant to prosecute the war to a successful conclusion. The Roundheads would require more decisive leadership if they were to gain the victory which the radicals craved.
This image clearly illustrates the importance of the Cromwellian cavalry at Marston Moor. Already wounded, Cromwell led his Ironsides across the field to engage with the Cavaliers at the crucial moment, putting them into flight. The superior discipline of the Parliamentary forces proved crucial in determining the war's outcome.