Seven Years' War: Frederick the Great defeats the allied armies of France and the Holy Roman Empire at the Battle of Rossbach.

The Seven Years' War, 1756 to 1763, was a Great Power conflict fought primarily in Europe, with significant subsidiary campaigns in North America and South Asia. The warring states were Great Britain and Prussia fighting against France and Austria, the respective coalitions receiving assistance from countries including Portugal, Spain, Saxony, Sweden, and Russia. Related conflicts include the Third Silesian War, French and Indian War, Third Carnatic War, Anglo-Spanish War (1762–1763), and Spanish–Portuguese War.

Frederick II was the monarch of Prussia from 1740 until his death in 1786. He was the last Hohenzollern monarch titled King in Prussia, declaring himself King of Prussia after annexing Royal Prussia from the Polish–Lithuanian Commonwealth in 1772. His most significant accomplishments include military successes in the Silesian wars, reorganisation of the Prussian Army, the First Partition of Poland, and patronage of the arts and the Enlightenment. Prussia greatly increased its territories and became a major military power in Europe under his rule. He became known as Frederick the Great and was nicknamed "Old Fritz".

The Holy Roman Empire, also known as the Holy Roman Empire of the German Nation after 1512, was a polity in Central and Western Europe, usually headed by the Holy Roman Emperor. It developed in the Early Middle Ages, and lasted for a millennium until its dissolution in 1806 during the Napoleonic Wars. For most of its history the Empire comprised the entirety of the modern countries of Germany, Czechia, Austria, the Netherlands, Switzerland, Slovenia, and Luxembourg, most of north-central Italy and southern Belgium, and large parts of modern-day east France and west Poland.

The Battle of Rossbach took place on 5 November 1757 during the Third Silesian War near the village of Rossbach (Roßbach), in the Electorate of Saxony. It is sometimes called the Battle of, or at, Reichardtswerben, after a different nearby town. In this 90-minute battle, Frederick the Great, king of Prussia, defeated an Allied army composed of French forces augmented by a contingent of the Reichsarmee of the Holy Roman Empire. The French and Imperial army included 41,110 men, opposing a considerably smaller Prussian force of 22,000. Despite overwhelming odds, Frederick managed to defeat the Imperials and the French.