In 1644 the Scots joined forces with Parliamentary forces to lay siege to the Royalist held city of York. In June 1644 Prince Rupert and his Cavaliers set out to rescue the Earl of Newcastle and his forces. On 2nd July the Royalists confronted the Parliamentarians at Marston Moor.

Edward Montagu and Thomas Fairfax, the leaders of the Parliamentary forces, decided to withdraw from Marston Moor towards Tadcaster in order to cut off any attempt by the Earl of Newcastle to escape. Prince Rupert decided to attack the retreating troops. This resulted in the Parliamentary army being ordered back to Marston Moor.

That afternoon Oliver Cromwell and his forces charged John Byron and his cavalry. His men, instead of pursuing Byron's cavalry, regrouped and returned to protect the infantry that had now come under attack from George Goring and his cavalry.

The Earl of Newcastle and his Whitecoat regiment made a heroic last stand and resisted repeated charges by the Parliamentary army until no more than 30 were left alive.

The battle lasted two hours. Over 3,000 Royalists were killed and around 4,500 were taken prisoner. The Parliamentary forces lost only 300 men. The city of York surrendered two weeks after the battle, ending Royalist power in the north of England. Prince Rupert rallied the survivors and retreated to Chester where he attempted to build a new Royalist army.