Charles I gathered an army and moved to the border of Scotland. He had sent the Marquis of Hamilton by sea to negotiate with the Scots while his army gathered. The Scots under the command of Alexander Leslie had prevented Hamilton landing in Scotland and the Scots marched south to meet the King.

The army Charles had put together was no match for the Scottish army under the command of Leslie and so the King signed the Treaty of Berwick. While the Scots returned home happy that they could deal with their own church affairs, Charles had no intensions of abiding by the terms of the treaty and used the treaty as a means of gaining time to plan his next move.

Alexander Leslie, the Scottish Field Marshall, with a force of some 20,000 soldiers marched into northern England.

At Newburn, a crossing on the River Tyne, the Scots met a force of English troops. The English, who were untrained and low on supplies, were easily defeated and the Scots marched on to the nearby town of Newcastle. The town fell to the Scots.

With the arrival of Prince Rupert, the Parliamentarian forces led by generals Leven, Fairfax and Manchester abandoned the siege of York and headed south. Rupert followed and attacked the rear of the column forcing the fleeing army to stop. The Parliamentarians held the higher and tactically better position on Long Marston Moor. The Duke of Newcastle and his Royalist men joined Prince Rupert to create an army of around 18,000 men while the Parliamentarians had a force of around 28,000 men and had better artillery. Late in the day the fighting began with an attack by Leven and Fairfax in the centre. The attack did not go well for the Parliamentarians and Leven and Fairfax left the battlefield. Whan all seemed lost a cavalry unit commanded by Oliver Cromwell on the left of the field attacked the Royalists and gained the upper hand. The Royalists were defeated leaving some three to four thousand of their men dead.

After his successes in Scotland Montrose decided to go to England to assist the king. As he marched south he met a Parliamentarian army lead by Leslie. Montrose's forces had been greatly reduced as sections of his army had returned home with their spoils of war. Montrose was outnumbered and defeated. Montrose escaped.