In the Battle of Königgrätz or Battle of Sadowa of July 3, 1866, the Austro-Prussian War was decided in favor of Prussia.

The Austrian army, led by Ludwig von Benedek , was concentrating just north of Hradec Králové (German Königgrätz) near the village of Sadová in eastern Bohemia, and the Prussians, led nominally by King Wilhelm I, but in reality by Chief of the General Staff Helmuth von Moltke, decided to converge their three armies (the First Army of Prince Friedrich Karl; the Army of the Elbe under Karl Herwarth von Bittenfeld ; and the Second Army, under Crown Prince Friedrich) on the Austrian positions.

The armies arrived in position by July 3, and in a heavy rainstorm, the First Army and the Army of the Elbe attacked the Austrian army at dawn, but the Crown Prince's Second Army, due to a telegraphic failure, was not notified and did not engage in the battle. A fierce Austrian counterattack held off the Prussians, whose attack was halted by 11 AM, but Benedek refused to call for a cavalry charge which might have won the battle.

At 2:30 PM the Crown Prince finally arrived, having been ordered to engage by a note sent by Moltke through a courier, and hit the Austrians, while the Prussian artillery pounded the Austrian center. The superiority of the Prussian "needle-gun" rifle, which was breech-loading and could be reloaded quickly and operated while lying prone, while the Austrians had to stand up after each shot to reload their obsolete muzzle-loading rifles, proved decisive, and Benedek was forced to order a withdrawal.

The battle was decisive in the war, and an armistice was agreed to almost immediately.