The Battle of Kolin was a major battle of the Seven Years' War that was fought in 1757 between the armies of Austria and Prussia in Bohemia.
While Frederick the Great had defeated the Austrians at the Battle of Prague in May 1757, another Austrian army under Leopold Joseph von Daun marched to Prague's relief, forcing Frederick to leave Ferdinand of Brunswick-Wolfenbuttel to maintain the siege of Prague as he and 34,000 Prussian troops confronted Von Daun's 54,000 troops at Kolin. Frederick planned to overwhelm the Austrian right wing with most of his army as his left wing held off Austrian attacks, but his forces inadvertently launched frontal attacks on the Austrian right wing too early. Austrian musket and artillery fire halted Frederick's advance, and, while an Austrian counterattack was defeated by Prussian cavalry, an attempt by Frederick to pour more troops into the battle and exploit a gap in the Austrian line was crushed by Austrian cavalry. As both sides' cavalry launched charges and counter-charges, Friedrich Bogislav von Tauentzien's guards enabled the Prussian army to escape, marking Frederick's first defeat. Frederick was forced to cancel his march on Vienna and lift his siege of Prague, retreating from Bohemia to Saxony.