|Covid-19|February 11 – King Henry VIII of England allies with Charles V, Holy Roman Emperor, against France.
February 21 – Battle of Wayna Daga: A joint Ethiopian-Portuguese force of 8,500 under Emperor Gelawdewos of Ethiopia defeats Imam Ahmad ibn Ibrahim al-Ghazi's army of over 14,000, ending the Ethiopian–Adal war.
King Gustav Vasa's troops crush the forces of Swedish peasant rebel Nils Dacke in battle, ending the uprising. Dacke escapes but is captured and killed in the summer.
Consolidating Act of Welsh Union: The Parliament of England establishes counties and regularises parliamentary representation in Wales.
April – Campaign of Suleiman: Suleiman the Magnificent, Ottoman Emperor, revives the Little War in Hungary.
May – Nicolaus Copernicus publishes De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres) in Nuremberg, offering mathematical arguments for the existence of the heliocentric universe, denying the geocentric model. Copernicus dies on May 24 in Frombork at the age of 70.
June – Andreas Vesalius publishes De humani corporis fabrica (On the Fabric of the Human Body), revolutionising the science of human anatomy.
July 1 – Treaty of Greenwich between England and Scotland (repudiated by Scotland December 11).
July 12 – King Henry VIII of England marries Catherine Parr. It is the sixth and last of Henry's marriages and the third of Catherine's. Princess Elizabeth attends the wedding. This month, the Parliament of England passes the Third Succession Act restoring the Princesses Mary and Elizabeth, Henry's daughters, to the line of succession to the English throne.
July 25–August 10 – Siege of Esztergom: Suleiman the Magnificent, Ottoman Emperor, besieges and takes Esztergom in Hungary from the Holy Roman Empire.
August 6–22 – Siege of Nice: Ottoman Empire and French forces (under the Franco-Ottoman alliance) led by Admiral Hayreddin Barbarossa besiege and take Nice.
August 25 – The first Europeans and firearms arrive in Japan
September–October – Landrecies in Picardy is besieged by forces under Charles V, Holy Roman Emperor, but the siege is withdrawn on the approach of the French army.
September – Campaign of Suleiman: Suleiman the Magnificent captures the Hungarian coronation city of Székesfehérvár. The city will be occupied by the Ottoman Empire for 145 years.
Martin Luther publishes On the Jews and Their Lies.
Mikael Agricola publishes Abckiria.
Lighthouse of Genoa completed in present form.
Indians in the Spanish Empire are declared free against the wish of local settlers.
January 18 (baptized) – Alfonso Ferrabosco, Italian composer (d. 1588)
January 31 – Tokugawa Ieyasu, Japanese shogun (d. 1616)
February 4 – Johannes Heurnius, Dutch physician (d. 1601)
February 4 – Giovanni Francesco Fara, Writer (d. 1591)
February 16 – Kanō Eitoku, Japanese painter (d. 1590)
February 18 – Charles III, Duke of Lorraine (d. 1608)
February 25 – Sharaf Khan Bidlisi, Emir of Bitlis (d. 1603)
March 7 – John Casimir of the Palatinate-Simmern, German prince and reigning count palatine of Simmern (d. 1592)
April 1 – François de Bonne, Duke of Lesdiguières, Constable of France (d. 1626)
April 11 – George John I, Count Palatine of Veldenz (d. 1592)
May 2 – Jan Moretus, Belgian printer (d. 1610)
June 8 – Petrus Albinus, German historian, local history researcher and poet (d. 1598)
June 29 – Christine of Hesse, Duchess Consort of Holstein-Gottorp (1465-1486) (d. 1604)
July 20 – Nils Svantesson Sture, Swedish diplomat (d. 1567)
August 3 – Nicasius de Sille, Dutch diplomat (d. 1600)
August 21 – Giovanni Bembo, Doge of Venice (d. 1618)
September 14 – Claudio Acquaviva, Italian Jesuit (d. 1615)
October 21 – Michael Hicks, English politician (d. 1612)
November 2 – Kasper Franck, German theologian (d. 1584)
November 8 – Lettice Knollys, Countess of Essex and later Countess of Leicester, lady-in-waiting to Elizabeth I of England (d. 1634)
December 3 – Alessandro Riario, Cardinal Priest (d. 1585)
December 29 – Catherine of Nassau-Dillenburg, daughter of William I (d. 1624)
Nicolas de Neufville, seigneur de Villeroy, 2nd Prime Minister of France (d. 1617)
Thomas Deloney, English novelist and balladeer (d. 1600)
Domenico Fontana, Italian architect (d. 1607)
Sonam Gyatso, 3rd Dalai Lama, first Dalai Lama (d. 1588)
François Pithou, French lawyer and author (d. 1621)
Hayyim ben Joseph Vital, rabbi and mystic (d. 1620)
Chen Lin, general of Ming dynasty
Giovanni Maria Nanino, Italian composer (d. 1607)
Federico Zuccari, Italian painter (d. 1609)
January 2 – Francesco Canova da Milano, Italian composer (b. 1497)
January 3 – Juan Rodríguez Cabrillo, Portuguese explorer (b. 1499)
January 9 – Guillaume du Bellay, French diplomat and general (b. 1491)
February 21 – Ahmad ibn Ibrahim al-Ghazi, Imam of Adal (in battle) (b. c. 1506)
March 6 – Baccio D'Agnolo, Florentine woodcarver (b. 1460)
May 24 – Nicolaus Copernicus, Polish mathematician and astronomer (b. 1473)
July 19 – Mary Boleyn, mistress of Kings Francis I of France and Henry VIII of England (b. 1500)
September 20 – Thomas Manners, 1st Earl of Rutland (b. 1492)
November 29 – Hans Holbein the Younger, German artist, active in England
George, Margrave of Brandenburg-Ansbach (b. 1484)
Francesco Spiera, Protestant Italian jurist (b. 1502)
Polidoro da Caravaggio, Italian painter (b. 1492; murdered)
Sultan Quli Qutb Mulk, founder of the Qutb Shahi dynasty of Golconda
Sebastian Franck, German freethinker (b. 1515)
Margaret Lee, sister of poet Thomas Wyatt (b. 1506)
Year 1543 (MDXLIII) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. It is one of the years sometimes referred to as an "Annus mirabilis" because of its significant publications in science, considered the start of the scientific revolution.