|Covid-19|January 22 – Impostor Mary Carleton is hanged at Newgate Prison in London for multiple thefts and returning from penal transportation.
February 10 – Première of Molière's comédie-ballet The Imaginary Invalid in Paris. During the fourth performance, on February 17, the playwright, playing the title rôle, collapses on stage, dying soon after.
March 29 – Test Act: Roman Catholics and others who refuse to receive the sacrament of the Church of England cannot vote, hold public office, preach, teach, attend the universities or assemble for meetings in England. On June 12, the king's Catholic brother, James, Duke of York, is forced to resign the office of Lord High Admiral because of the Act.
April 27? – Jean-Baptiste Lully's first opera, Cadmus et Hermione, is premièred in France.
May 17 – In America, trader Louis Joliet and Jesuit missionary-explorer Jacques Marquette begin exploring the Mississippi River and the Great Lakes.
June 7 – First Battle of Schooneveld: In a sea battle of the Third Anglo-Dutch War, fought off the Netherlands coast, the Dutch Republic fleet (commanded by Michiel de Ruyter) defeats the allied Anglo-French fleet commanded by Prince Rupert of the Rhine.
June 14 – Second Battle of Schooneveld: The Dutch fleet again defeats the jointed Anglo-French fleet.
June 17 – French explorers Father Jacques Marquette and Louis Joliet reach the headwaters of the Mississippi River and descend to Arkansas.
July 6 – French troops conquer Maastricht.
July 11 – The Netherlands and Denmark sign a defense treaty.
July 24 – Edmund Halley enters Queen's College at Oxford, as an undergraduate.
August 8 – In the American colonies, a Dutch battle fleet of 23 ships demands the surrender of New York.
August 9 – Dutch forces under Admiral Cornelis Evertsen de Jonge recapture New York from the English (regained by the English in 1674).
August 21 – Battle of Texel (Kijkduin): The Dutch fleet under Michiel de Ruyter defeats the English and French fleet. This prevents England's Blackheath Army from landing in Zeeland
August 30 – Leopold I, Spain, Netherlands and the Lutherans form an anti-French covenant.
September 12 – William, Prince of Orange occupies Naarden.
November 9 – King Charles II of England removes Anthony Ashley Cooper, 1st Earl of Shaftesbury, from his position as Lord Chancellor.
November 11 – Polish and Lithuanian military units under the command of soon-to-be-king Jan Sobieski defeat the Turkish army in the Battle of Khotyn. In this battle, rockets of Kazimierz Siemienowicz are successfully used.
November 13 – Dutch troops commanded by Raimondo Montecuccoli and William, Prince of Orange conquer Bonn.
November 14 – Christopher Wren is knighted.
November 23 – James, Duke of York, marries Mary of Modena.
France begins its expedition against Ceylon.
Chelsea Physic Garden, the second oldest botanic garden in England, is founded by the Society of Apothecaries for the study of medicinal and other plants.
The Mitsui family's trading and banking house is founded in Japan.
The stalactic grotto of Antiparos (Aegean Sea) is discovered.
Archpriest Petrovich Avvakum writes his Zhitie (Life) as the first Russian autobiography.
January 31 – St. Louis Maria Grignion de Montfort, French Missionary Priest (d. 1716)
April 27 – Claude Gillot, French artist (d. 1722)
July 20 – John Dalrymple, 2nd Earl of Stair, Scottish soldier and diplomat (d. 1747)
August 8 – John Ker, Scottish spy (d. 1726)
August 10 – Johann Conrad Dippel, German alchemist (d. 1734)
August 11 – Richard Mead, English physician (d. 1754)
October 26 – Dimitrie Cantemir, Moldavian linguist and scholar (d. 1723)
December 30 – Ahmed III, Ottoman Sultan (d. 1736)
date unknown – Mir Wais Khan Hotaki, Persian Governor of Kandahar (d. 1715)
February 17 – Molière, French writer and actor (b. 1622)
March 15 – Salvator Rosa, Italian painter and poet (b. 1615)
March 20 – Augustyn Kordecki, Polish prior (b. 1603)
June 18 – Jeanne Mance, French Canadian settler (b. 1606)
June 25 – Charles de Batz-Castelmore d'Artagnan, French Soldier (b. 1611)
July 4 – Robert Moray, English freemason.
August 17 – Regnier de Graaf, Dutch physician and anatomist (b. 1641)
August 21 – Henry Grey, 1st Earl of Stamford, English soldier (b. c. 1599)
October 13 – Kristoffer Gabel, Danish statesman (b. 1617)
October 17 – Thomas Clifford, 1st Baron Clifford of Chudleigh, English statesman (b. 1630)
November 10 – Michał Korybut Wiśniowiecki (b. 1640)
December 15 – Margaret Cavendish, English writer (b. 1623)
December 31 – Oliver St John, English statesman and judge (b. c. 1598)
1673 (MDCLXXIII) was a common year starting on Sunday (dominical letter A) of the Gregorian calendar and a common year starting on Wednesday (dominical letter E) of the Julian calendar, the 1673rd year of the Common Era (CE) and Anno Domini (AD) designations, the 673rd year of the 2nd millennium, the 73rd year of the 17th century, and the 4th year of the 1670s decade. As of the start of 1673, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.