Henry successfully led Prussian armies as a general during the Third Silesian War (1756–1763, part of the Seven Years' War). He greatly distinguished himself during his brother's victory at the Battle of Prague and fought heroically during the Prussians' subsequent defeat at Kolin. After the Prussian Army's initial success against one wing of the joint Russian and Austrian Armies in the Battle of Kunersdorf, Henry urged his brother Frederick to stop attacking. The king, who had already sent a message of victory to Berlin, pressed the attack. The day ended with a virtually destroyed Prussian army, a virtually defenseless Kingdom of Prussia, and a complete victory by the Russo-Austrian force. Afterwards, Henry reorganized the routed Prussian forces. Frederick came to rely on his brother as commander of the Prussian forces in the east, Frederick's strategic flank. Henry later won his most famous victory at Freiberg in 1762, the final battle of the war between Austria and Prussia; during subsequent peace negotiations, Frederick wrote to him, "You alone have the honor of breaking down Austrian obstinacy."