1703

January–March

• January 9 - The Jamaican town of Port Royal, a center of trade in the Western Hemisphere and at this time the largest city in the Caribbean, is destroyed by a fire. British ships in the harbor are able to rescue much of the merchandise that has been unloaded on the docks, but the inventory in market-places in town is destroyed.
• January 14 - 1703 Apennine earthquakes: The magnitude 6.7 Norcia earthquake affects Central Italy with a maximum Mercalli intensity of XI. With a death toll of 6,240–9,761, it is the first in a sequence of three destructive events.
• January 16 - 1703 Apennine earthquakes: The magnitude 6.2 Montereale earthquake causes damage at Accumoli, Armatrice, Cittareale and Montereale, with a maximum Mercalli intensity of VIII.
• January 30 - Akō incident: In Japan, forty-seven rōnin assassinate daimyō Kira Yoshinaka, the enemy of their former lord Asano Naganori, at his own mansion as a vengeance; for which they are compelled to commit suicide on March 20.
• February 2 - 1703 Apennine earthquakes: The magnitude 6.7 L'Aquila earthquake affects Central Italy, with a maximum Mercalli intensity of X. In the final large event, damage occurs as far distant as Rome, with landslides, liquefaction, slope failures and at least 2,500 deaths.
• February 20–March 10 - War of the Spanish Succession: Siege of Kehl - French forces under the command of the Duc de Villars capture the fortress of the Holy Roman Empire at Kehl, opposite Strasbourg on the Rhine.
• February - Soldiers at Fort Louis de la Mobile celebrate Mardi Gras in Mobile, starting the tradition for Mobile, Alabama.
• March 1 - The Recruiting Act 1703 goes into effect in England, providing for the forcible enlistment of able-bodied but unemployed men into the English Army and Royal Navy in order to fight in Queen Anne's War in North America. The Act expires at the end of February 1704.
• March 15 - The landmark English court case of Rose v Royal College of Physicians is decided by the Court of Queen's Bench, beginning the end of the monopoly that the Royal College of Physicians has over the practice of medicine.
• March 19 - The Siege of Guadeloupe begins as an English expeditionary force, led by Christopher Codrington and Hovenden Walker, lands at Basse-Terre and attempts to take over the French-held island. The English fleet departs on May 15 after being unable to capture Guadeloupe.
• March 20 - 46 of the forty-seven rōnin of Japan carry out an order of seppuku for the killing they committed on January 30. The punishment is given by the shogun Tokugawa Tsunayoshi. The story continues to be dramatized more than 300 years later in Chūshingura theater, novels and film.
• March 21 - Jeanne Guyon is freed from the Bastille in Paris after more than seven years imprisonment for heresy.

  April–June

• April 21 - The Company of Quenching of Fire is founded in Edinburgh, Scotland.
• May 26 - Portugal joins the Grand Alliance.
• May 27 - The city of Saint Petersburg, Russia is founded, following Peter the Great's reconquest of Ingria from Sweden during the Great Northern War.
• June 15 - Rákóczi's War of Independence: Hungarians rebel under Prince Francis II Rákóczi.
• June 19 - Bavarian troops, who during the so-called Bavarian Rummel have invaded Tyrol, besiege Kufstein. Fires break out on the outskirts that engulf the town, destroy it and reach the powder store of the supposedly impregnable fortress. The enormous gunpowder supplies explode and Kufstein has to surrender on June 20. This same day the Tyrolese surrender in Wörgl; two days later Rattenberg is captured and Innsbruck is cleared without a fight on June 25.
• June 30 - Battle of Ekeren : The French surround a smaller Dutch force, which however breaks out and retires to safety.
• June - The completed 1703 Icelandic census is presented in the Althing, the first complete census of any country.

  July–September

• July 26 - After their victories at the Pontlatzer Bridge and the Brenner Pass, Tyrolese farmers drive out the Bavarian Elector, Maximilian II Emanuel, from North Tyrol and thus prevent the Bavarian Army, which is allied with France, from marching on Vienna during the War of the Spanish Succession. This success, at low cost, is the signal for the rebellion of the Tyrolese against Bavaria, and Elector Maximilian II Emanuel has to flee from Innsbruck. The Bavarian Army withdraws through Seefeld in Tirol back to Bavaria.
• July 29–31 - Daniel Defoe is placed in a pillory in London, then imprisoned until mid-November for the crime of seditious libel after publishing his satirical political pamphlet The Shortest Way with the Dissenters.
• August 23 - Edirne event: Sultan Mustafa II of the Ottoman Empire is dethroned.
• September 7 - War of the Spanish Succession: The town of Breisach is retaken for France by Camille d'Hostun, duc de Tallard.
• September 12 - War of the Spanish Succession: Habsburg Archduke Charles is proclaimed King of Spain, but never exercises full rule.

  October–December

• October 11 - Nine Roman Catholic residents of the French village of Sainte-Cécile-d'Andorge are massacred by a mob of more than 800 French Huguenot Protestants, the Camisards. A reprisal against Protestants in the nearby village of Branoux is made less than three weeks later.
• October 23 - Hannah Twynnoy, a 24-year-old barmaid in Malmesbury, Wiltshire, becomes the first person to be killed in Great Britain by a tiger. While working at the White Lion Inn, where a group of wild animals is on exhibit, she is mauled after bothering the tiger.
• October 30 - More than 47 Huguenots in the village of Branoux-les-Taillades are massacred by Roman Catholic vigilantes in reprisal for the October 11 attack on nearby Sainte-Cécile, slightly more than two miles away.
• November 15
• * War of the Spanish Succession: Battle of Speyerbach - The French defeat a German relief army, allowing the French to take the besieged town of Landau two days later, for which Tallard is made a Marshal of France.
• * Rákóczi's War of Independence: Battle of Zvolen - The Kurucs defeat the Austrians and their allies.
• November 19 - The so-called Man in the Iron Mask dies in the Bastille. He is buried under the name of "Marchioly".
• November 30 - Isaac Newton is elected president of the Royal Society of London, a position he will hold until his death in 1727.
• December 7–10 - The Great Storm of 1703, an extratropical cyclone, ravages southern England and the English Channel, killing at least 8,000, mostly at sea. The Eddystone Lighthouse off Plymouth is destroyed in the storm together with its designer Henry Winstanley and many buildings on land are damaged.
• December 27 - Portugal and England sign the Methuen Treaty, which gives preference to Portuguese wines imported into England.
• December 28 - Ahmed III succeeds the deposed Mustafa II as Ottoman Emperor.

  Date unknown

• French-born imposter George Psalmanazar arrives in London.
• Between 1702 and 1703 – An epidemic of smallpox breaks out in Quebec, in which 2,000-3,000 people die.

  Births

January–March

• January 1 - Heinrich Sigismund von der Heyde, Prussian army commander
• January 2 - George Cholmondeley, 3rd Earl of Cholmondeley, English politician
• January 3 - Daniel-Charles Trudaine, French administrator and civil engineer
• January 5
• * James Hamilton, 5th Duke of Hamilton, Scottish peer
• * Paul d'Albert de Luynes, French archbishop
• January 8 - André Levret, French obstetrician, medical practitioner in Paris
• January 10 - Christoph Birkmann, German theologian and minister
• January 15
• * Henriette Louise de Bourbon, French princess by birth, member of the House of Bourbon
• * John Brydges, Marquess of Carnarvon, English politician
• * Johann Ernst Hebenstreit, German physician and naturalist
• January 20 - Joseph-Hector Fiocco, Belgian composer and violinist
• January 22 - Antoine Walsh, Irish-French slave trader and Jacobite
• January 29 - Carlmann Kolb, German priest
• January 31 - André-Joseph Panckoucke, French author and bookseller
• February 2 - Richard Morris, Welsh writer and editor
• February 3 - Jean Philippe de Bela, French military figure and Basque writer and historian
• February 4
• * Jean Saas, French historian and bibliographer
• * Andrew Stone, significant figure in the British royal circle, Member of Parliament
• February 5 - Gilbert Tennent, Irish-born religious leader
• February 8
• * Corrado Giaquinto, Italian Rococo painter
• * François-Pierre Rigaud de Vaudreuil, soldier in New France
• February 13 - Robert Dodsley, English bookseller, poet, playwright and miscellaneous writer
• February 27 - Lord Sidney Beauclerk, English politician and fortune hunter
• March 1 - Philip Tisdall, Attorney-General for Ireland
• March 4 - Nicolas René Berryer, French magistrate and politician
• March 5 - Vasily Trediakovsky, Russian poet
• March 10 - Peter Warren, British Royal Navy officer
• March 21 - Georg Andreas Sorge, Thuringian organist
• March 23 - Cajsa Warg, Swedish cookbook author