Seven Years' War, a contest involving the principal European powers from 1756 to 1763, and extending to the four quarters of the globe. The empress Maria Theresa, though forced in the treaty of Dresden (1745) to confirm Frederick the Great in the possession of Silesia, did not relinquish the hope of recovering it. She determined to secure a coalition that would crush the king of Prussia, and made active preparations for war. She courted the alliance of Louis XV., and by flattering Mme. de Pompadour gained over the French court. The friendship between Great Britain and Austria was severed, and the system of European alliances was dissolved. George II., who was already involved in the French and Indian war, perceived that a continental conflict would at once expose his Hanoverian dominions to French invasion, and to protect himself against this danger he concluded a defensive treaty with Frederick the Great on Jan. 16, 1756. Maria Theresa now openly consummated the alliance with France (May 1). Elizabeth of Russia, whom Frederick had provoked by his satire, and Augustus III., king of Poland and elector of Saxony, who was eager to wipe out the disgrace of the previous war, joined the league; the mass of the German states followed; Sweden was gained by the hope of conquests in Pomerania; and a coalition was effected the most powerful that Europe had ever witnessed.

The main events of the seven years' struggle in Europe have been described under Frederick II. Saxony, Bohemia, Silesia, and Brandenburg were the principal theatres of the war. Here the Prussian king, seconded by his brother Prince Henry, Schwerin, Keith, Seydlitz, the prince of Bevern, Ziethen, Dohna, Lewald, and others, was opposed to the Austrian commanders Daun, Laudon, Browne, and Charles of Lorraine, and to the Russian generals Apraxin, Fermor, Soltikoff, and Tcher-nitcheff. In western Germany, where the incapable duke of Cumberland was defeated at Hastenbeck by the French under D'Estrées (July 26, 1757), and forced by Marshal Richelieu to sign the capitulation of Closter Seven (Klosterseeven), the glory of the Prussian arms was sustained by Duke Ferdinand of Brunswick, who frustrated the efforts of Clermont, Contades, Soubise, and Broglie, and by victories like those of Crefeld (June 23, 1758) and Minden (Aug. 1, 1759). Still, Frederick was on the point of being overwhelmed by numbers, when the death of the empress Elizabeth (Jan. 5, 1762) and the accession of Peter III. changed the state of affairs. France, while lavishing her armies in the service of Austria, and her treasures in subsidizing a dozen allies, was compelled to witness the downfall of her colonial power.

A French expedition under Marshal Richelieu had succeeded in conquering Minorca from the English, whom the first reverses in America and the fear of a French invasion had plunged into the utmost despondency; but the nation rallied, and under the guidance of the elder Pitt entered upon a remarkable career of success. Louisburg was taken in 1758, Quebec fell in the following year, all Canada submitted, and Guadeloupe (1759), Martinique (1762), and other West India islands were conquered. Admiral Hawke won a brilliant victory over the French fleet in the bay of Quiberon in November, 1759, and the island of Belleisle, on the coast of France, was taken in June, 1761. Clive humbled the French power in India, and laid the foundations of a mighty empire. On the African coast the English were equally successful. France, where Choiseul assumed the ministry in 1758, sought to restore her fortunes by a new alliance, and in 1761 concluded the family compact, which united the various branches of the house of Bourbon. A declaration of war between England and Spain followed.

While Charles III., the Spanish king, unsuccessfully attacked Portugal, the English reduced Havana, where they obtained immense booty (August, 1762), and made themselves masters of the Philippines. The war was terminated by the treaty of Paris (Feb. 10, 1763) between England, France, and Spain, the preliminaries to which had been signed on Nov. 3, 1762, and by that of Huberts-burg (Feb. 15, 1763) between Prussia and Austria. Great Britain was aggrandized at the expense of the house of Bourbon, while the terms of the peace provided for a mutual restitution of conquests on the continent of Europe. Silesia remained in possession of Frederick. England retained her Canadian and a portion of her West Indian conquests, as well as those on the river Senegal, and acquired Florida from Spain, to whom as a compensation France ceded Louisiana. Martinique, Guadeloupe, and other islands (to which Santa Lucia was added), and Pondicherry were restored to France, and the privilege of the gulf of St. Lawrence and a portion of the Newfoundland coast was secured to French fishermen.

In return Louis XV. agreed to dismantle Dunkirk on the sea side. - See Schäfer, Geschichte des siebenjährigen Kriegs (2 vols., Berlin, 1867-'8), and Ranke, Ursprung des siebenjährigen Krieges (Leipsic, 1871).