The invasion of Silesia by Frederick II of Prussia (16 Dec. 1740) followed the death of Emperor Charles VI (20 Oct.) touched off a series of continental wars with France, now allied with Prussia (5 June 1741), invading southern Germany. With the signing of the Second Family Compact (25 Oct. 1743) between France and Spain, France joined the war against England (15 Mar. 1744). Neither side prosecuted the war in America vigorously. The French made an unsuccessful assault on Annapolis Royal (Port Royal, Nova Scotia, 1744), and an expeditionof New Englanders under WIlliam Pepperrell (1696-1759, Bt., 1746) in cooperation with a fleet under Sir Peter Warren captured Ft. Louisbourg (16 June 1745). The Maine towns were raided by the French and Native Americans (from Aug. 1745). In New York William Johnson (p. 1072), Mohawk Valley Indian trader and commissary of New York for Indian affairs (1746), succeeded in getting the Iroquois on the warpath, with resultant French retaliatory raids on Saratoga (burned, 28-29 Nov. 1745) and Albany. The inconclusive Treaty of Aix-la-Chapelle (18 Oct. 1748) restored the status quo ante in the colonies and returned Louisbourg to France.

King George's War (1744-1748), the third of the French and Indian wars, was known as the War of Austrian Succession in Europe, where it began in 1740. The war included most of the European nations in a complicated series of alliances. It began after the death of Charles VI, the Holy Roman Emperor and ruler of the Hapsburg lands. The Archduches Maria Theresa succeeded her father but there were counterclaimants. Fighting began when King Frederick II of Prussia invaded Austrian-held Silesia. In America and elsewhere in the world, France and England fought for colonial power and possessions. The French unsuccessfully attacked Port Royal, Nova Scotia, in 1744, the year in which fighting broke out in America.

• French and Indian forces began the year (1745) with raids on English fortifications in Maine.
• Fort Louisbourg, a powerful French stronghold on Cape Breton Island in Nova Scotia, was captured by New Englanders under William Peppercell and an English fleet under Sir Peter Warren.
• Saratoga, New York was attacked and burned by the French and Indian forces after the English had succeeded in persuading the Iroquois league to enter the war against the French.

The Treaty of Aix-la-Chapelle was signed on October 18, 1748, ending the War of the Austrian Succession, known in America as King George's War (1744-1748). For the most part it restored the status quo in the New World, returning Fort Louisbourg, on Cape Breton Island in Canada, to France. The New Englanders, whose forces had fought brilliantly to capture heavily defeated Louisbourg, were outraged. As a result, the English Crown agreed to bear the cost of the expedition. Gret Britain's privilege of transporting slaves to Spanish America was renewed, but the treaty turned out to be merely a truce before the last and greatest of the French and Indian Wars.