Basically, as far as Britain is concerned, the most important event would appear to be the defeat of Bonnie Prince Charlie at the battle of Culludon. This cannot be taken out of context, however. One year in isolation means nothing. What came before (caused it?) and what followed, and why, are also important. For example - why did Britain get a king from Holland? Why was Bonnie Prince Charlie fighting? What for? Who was he?
see below for sources/info:
The Highlanders are massacred at the Battle of Culloden,
Cumberland wins against the Jacobites. Charles Edward, the Young Pretender, escapes to France.
Mary Leapor dies.
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political events
The Battle of Falkirk January 17 gives the Jacobite pretender Charles Edward Stuart and his Highlanders a victory over the British dragoons. Lord George Murray, 51, commands the 8,000-man Jacobite army, Lieutenant General Henry Hawley the 8,000-man Royalist force. Seven guns, all the Royalist baggage, and as many as 600 prisoners fall into Jacobite hands (the Royalists also lose 350 killed and wounded, the Jacobites 50 killed, 80 wounded), but the Jacobite pretender's secretary Sir John Murray (of Broughton), 27, suffers a nervous collapse in March, the Jacobite commissary suffers as a result, and the Young Pretender is headed for disaster.
The Battle of Culloden Moor in Inverness-shire April 16 ends Stuart efforts to regain the British throne. William Augustus, duke of Cumberland, has stopped at Nairn to celebrate his 25th birthday, "Bonnie Prince Charlie" has marched his 7,000 starving Highlanders across the moors by night to surprise the British. They have turned back exhausted. Cumberland's 9,000-man army arrives with 15 infantry battalions, four regiments of dragoons, some Scottish volunteer units, and 16 guns (the Scots have only 12). Cumberland opens fire, the Scots find themselves surrounded, and they flee the field, leaving behind all their guns plus nearly 1,000 dead, many of bayonet wounds. Lord George Murray withdraws to Ruthven, having objected to making a stand at Culloden on grounds that the terrain was unfavorable. British dragoons hunt down and massacre most who have survived the carnage, and although his men do take 558 prisoners, the British commander remains in Scotland for 3 months, rounding up some 3,500 men, executing about 120, burning villages, seizing cattle, and gaining the nickname "Butcher Cumberland." "Bonnie Prince Charlie" dismisses Lord George Murray, and although Simon Fraser, 11th Lord Lovat, urges him to remain, the Young Pretender escapes to the Isle of Skye in the Inner Hebrides June 29 disguised as Betty Burke, an Irish spinning maid to farmer's daughter Flora Macdonald, 23, who conducts him to safety from Benbecula to Portree at great risk to her own life. The British capture Lord Lovat, the Young Pretender gets away to France September 20, the British imprison Macdonald briefly in the Tower of London, and they will hold her for the next year aboard a troopship in Leith Roads and at London. They forbid anyone to wear the tartan, a ban that will continue until 1782. Sir John Murray (of Broughton) turns king's evidence at his trial, testifies against those whom he believes have failed the Jacobite cause, and will be pardoned in 1748.
French troops occupy Brussels February 21 and take Antwerp in the continuing War of the Austrian Succession (see 1745). The Battle of Rocoux near Liège October 11 gives the Marshal de Saxe, now 49, a victory that frees the Netherlands from Austria. His 120,000-man army has far outnumbered the 90,000 allies (see 1747).
Spain's first Bourbon king Felipe (Philip) V dies at Madrid July 9 at age 62, almost completely insane after a 46-year reign that was interrupted in 1724 by his first son's brief reign. His army has defeated a 56,000-man French army at Piacenza June 15; his second son by his first wife, Maria Louisa of Savoy, is 33 and will reign until 1759 as Ferdinand VI. France's dauphine, the former Spanish infanta, dies in July after giving birth to a daughter.
Denmark's Kristian VI dies at Horsholm August 6 at age 47 after a weak 16-year reign. His 23-year-old son has married the daughter of Britain's George II and will reign until 1766 as Frederik V.
Madras falls October 20 to French forces under the colonial governor Joseph François Dupleix, 49, in an extension of the War of the Austrian Succession. The 47-year-old Bertrand-François Mahé, comte de La Bourdonnais, has made the military success possible by blockading Madras in his role as commander of French naval forces in the Indian Ocean, but Dupleix has La Bourdonnais removed from his position as governor of Mauritius (Ile de France) and Réunion (Ile de Bourbon) on charges of corruption; the British capture La Boudonnais on his voyage back to France, but he is permitted to return home on parole.
science
French physicist-clergyman Jean-Antoine Nollet, 46, demonstrates to Louis XV the wonders of the Leyden jar (Kleistian jar) discovered last year: he sends a harmless current through a chain of 180 royal guards. English physician-scientist William Watson constructs a more sophisticated version of the Leyden jar (Kleistian jar), coating the inside and outside of the vial with metal foil to increase its storage capacity. He will use it next year to transmit an electric spark through a wire across the Thames at Westminster Bridge.
Benjamin Franklin begins experiments with electricity at Philadelphia. Franklin will improve the Leyden jar (Kleistian jar) invented last year by replacing its water with pulverized lead, and he will invent an adaptation of the Leyden jar—a foil-coated pane of glass that will be called the Franklin pane (see 1747; Priestley, 1767).
medicine
German physician George Erhard Hamberger, 47, gives the first description in medical literature of the duodenal ulcer that will plague modern society.
religion
The Countess of Huntingdon's Connexion is founded by the 29-year-old English widow Selina Hastings (née Shirley), countess of Huntingdon, whose sect of Calvinist Methodists will be prominent in the evangelical revival that is sweeping Britain. Daughter of Washington Shirley, 2nd Earl Ferrers, she married Theophilus Hastings, 9th earl of Huntingdon, in 1728, joined John Wesley's Methodist society in 1739, and became the "elect lady" of the movement following her husband's death.
education
Princeton University has its beginnings in the College of New Jersey founded at Newark by Presbyterian ministers who include Aaron Burr, 30. Classes open in a building that also houses the city courthouse and jail. Burr will be president of the college from 1748 to 1757, moving it to Princeton in 1756, and it will adopt the name Princeton University in 1896 (see Nassau Hall, 1756).
communications, media
The electric telegraph is pioneered by the French abbé and physicist Jean-Antoine Nollet, who assembles 200 white-robed Carthusian monks, has them form a human chain that stretches for more than a kilometer, lets each one hold the end of a 25-foot length of iron wire in each hand, connects the last wire to a Leyden jar (Kleistian jar), makes them leap simultaneously into the air when the Leyden jar is discharged, and demonstrates that electricity can be transmitted over the full distance (see semaphore, 1793; Henry, 1831).
Printer-editor John Peter Zenger dies at New York July 28 at age 49. His widow and son will continue publication of his New-York Weekly Journal until 1751.
literature
Nonfiction:Pensées philosiphiques by French man of letters Denis Diderot, 32.
art
Painting:Captain John Hamilton and The Eliot Family by English painter Joshua Reynolds, 23; Moses Brought Before Pharaoh's Daughter by William Hogarth; The Vegetable Market at San Giacomo di Rialto by Antonio Canaletto, who moves to London, where he will remain for 10 years except for two short visits home to Venice; The Milliner (La Marchande de Modes) by François Boucher.
agriculture
English grain prices continue to fall as they have been doing for 30 years and will continue to do for another 10. Death rates will fall, too, as more people are able to afford better diets (see Burke's Act, 1773).
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Bonne Prince Charlie is defeated at the Battle of Culloden