marston moor

The Civil War was going badly for Royalist forces in the north of England. The Marquess of Newcastle was forced to fall back on the fortified city of York, where he was besieged by Parliamentary armies under Sir Thomas Fairfax.

Prince Rupert led a relief force of perhaps 7000 cavalry and as many footsoldiers north to the relief of the city.
Fairfax broke off the siege and marched his men south to prevent Rupert from reaching the approaches to York. The ever-daring Rupert surprised the Parliamentary generals by marching around their position and reaching the city anyway.
The Battle
Never one to pull back from a fight, Rupert now ordered his tired men out from York to surprise the enemy. They met a numerically superior force numbering perhaps 27,000 men.
By the time the armies were in position it was late in the day, and Rupert, convinced that his foe would not attack until the morning, left the field in search of his supper. Lord Newcastle, perhaps more reprehensibly, retired to his coach for a quiet smoke.
The Parliamentary army surprised the royalist totally by an attack which must have begun just as dusk was falling at 7pm. The fierce fighting lasted for several hours, eerily illuminated by a harvest moon. The royalist cavalry under the returned Rupert was ousted after fierce fighting, but it was the infantry that won the day (or night, in this case).
The Result
The Royalists lost as many as 3000 men, plus their artillery train. York was forced to surrender to Parliament and the north of England was effectively lost to the king.
Prince Rupert lost his glowing reputation of invincibility in battle, but Marston Moor made the reputation of another man; Oliver Cromwell made a name for himself for his role in defeating the Royalist cavalry.