1740
October 17 - Ivan VI becomes Czar of Russia.
October 20 - The War of the Austrian Succession (1740–1748), also known as King George's War in North America, and incorporating the War of Jenkins' Ear with Spain, involved nearly all the powers of Europe in the struggle to break up the empire. The spark that ignites the war is the death of Austrian Emperor Charles VI, who leaves no Habsburg male heir to the throne. His daughter, Maria Theresa, succeeded him as Queen of Hungary, Croatia and Bohemia, Archduchess of Austria and Duchess of Parma. Her father had been Holy Roman Emperor, but Maria Theresa was not a candidate for that title, which had never been held by a woman; the plan was for her to succeed to the hereditary domains, and her husband, Francis Stephen, to be elected Holy Roman Emperor. The complications involved in a female Habsburg ruler had been long foreseen.
1741
July 15 - Alexei Chirikov sights land in Southeast Alaska. He sends men ashore in a longboat, making them the first Europeans to visit Alaska. On July 28, Captain Bering discovers Mount St Elias, Alaska.
September 14 - George Frederick Handel finishes "Messiah" oratorio, after working on it non-stop for 23 days. On April 13, 1742, Handel's "The Messiah" premieres in Dublin.
Winter 1740-1741 - Benjamin Franklin begans planning for what has come to be called the "Franklin Stove" in Philadelphia, the largest city in America with a population of 13,000.
1742
January 14 - Edmond Halley (born 1656), astronomer and discoverer of Halley's Comet, dies.
July 7 - English and Spanish forces skirmished on St. Simons Island, Georgia, in an encounter later known as the Battle of Bloody Marsh. The Spanish attempt to invade Georgia during the War of Jenkins' Ear ended in victory for the British.
December 2 - The Pennsylvania Journal first appears in print in the United States.
1743
April 13 - Thomas Jefferson, 3rd President of the United States, is born.
June 27 - As the War of Austrian Succession continues, Austrian armies drive French and Bavarian troops out of Bavaria. Britain's 59-year-old George II personally leads a 50,000-man allied Pragmatic army of British, Austrian, Hessian, and Hanoverian troops that defeats 70,000 French in the Battle of Dettingen, some 70 miles east of Frankfurt.
1744
February 22–23 – As the War of Austrian Succession continues, the British fleet is defeated by a Franco-Spanish fleet in the Battle of Toulon. On March 15, France declares war on Great Britain. On April 20 at the Battle of Villafranca, a joint French and Spanish force defeats Britain and Sardinia. The third French and Indian War, known as King George's War, breaks out at Port Royal, Nova Scotia.
September 25 – King Frederick William II of Prussia (d. 1797)is born.
August 26 – Prominent Virginia planter William Byrd II (b. 1674) dies.
1745
May 11 – In the War of Austrian Succession, French forces defeat an Anglo-Dutch-Hanoverian army including the Black Watch at the Battle of Fontenoy. On June 4, Frederick the Great destroys the Austrian army at the Battle of Hohenfriedberg. On September 12, Francis I is elected Holy Roman Emperor with the support of his wife, Maria Theresia of Austria. He is the successor of Charles VII Albert of Bavaria, an enemy of Habsburg. On December 25, the Treaty of Dresden gives Prussia full possession of Silesia.
August 19 – The Jacobite Rising begins at Glenfinnan, Scotland, with Bonnie Prince Charlie raising an army from the clans to supported his bid for the throne. On December 4, the Jacobite Army reaches Derby; two days later it begins retreat. On September 21 at the Battle of Prestonpans, near Edinburgh, British forces are defeated. On December 19, the Jacobite army led by Bonnie Prince Charlie, on retreat from Derby, was defeated by the Duke of Cumberland at the Battle of Clifton Moor near Penrith, Cumberland.
