1540

January–June

• January - Dunstable Priory falls prey to Henry VIII of England's Dissolution of the Monasteries.
• January 6 - King Henry VIII of England marries Anne of Cleves, his fourth Queen consort. The marriage lasts six months and ends in divorce in July.
• February 14 - Charles V, Holy Roman Emperor, enters Ghent without resistance, and executes the rebels.
• March - Waltham Abbey is the final priory to fall prey to the Dissolution of the Monasteries.
• May 17 - Battle of Kannauj: Sher Shah Suri defeats and deposes Mughal Emperor Humayan, establishing the Sur Empire.

  July–December

• July 7 - Coronado captures Hawikuh, at this time known as part of Cíbola, but fails to find the legendary gold.
• July 9 - King Henry VIII of England divorces Anne of Cleves, his fourth Queen consort.
• July 28 - One of the most important political figures of the reign of Henry VIII of England, Thomas Cromwell, is executed on order from the king, on charges of treason. Henry marries his fifth wife, Catherine Howard, on the same day.
• August 15 - In Peru, the Spanish captain Garcí Manuel de Carbajal founded the Villa Hermosa de Arequipa, and one year after, Charles V of Germany and I of Spain gave the valley a status of 'city' by Royal Decree.
• September - Gibraltar is sacked by the fleet of Barbary pirate Ali Hamet, a Sardinian renegade in the service of the Ottoman Empire, and many of its leading citizens are taken as captives to Peñón de Vélez de la Gomera in Morocco. This leads to construction of the defensive Charles V Wall, at this time known as the Muralla de San Benito.
• September 3 - Gelawdewos succeeds his father Lebna Dengel, as Emperor of Ethiopia.
• September 27 - The Society of Jesus is approved by Pope Paul III, in his bull Regimini militantis Ecclesiae.
• October 1 - Battle of Alborán: A Habsburg Spanish fleet, under the command of Bernardino de Mendoza, destroys an Ottoman fleet, commanded by Ali Hamet, off Alborán Island in the Mediterranean.
• October 18 - An expedition led by Spanish conquistador Hernando de Soto destroys the fortified village of Mabila in modern-day Alabama, killing paramount chief Tuskaloosa.

  Date unknown

• Antwerp is besieged for three days, by Maarten van Rossum.
• Georg Joachim Rheticus publishes De libris revolutionum Copernici narratio prima in Danzig, an abstract of Copernicus' as yet unpublished De revolutionibus orbium coelestium, and the first printed publication of Copernican heliocentrism.
• Europe is hit by a heat wave and drought lasting for about seven months. Rivers such as the Rhine and Seine dry up, and many people die from dysentery and other illnesses, caused by lack of safe drinking water. However, this year's vintage from Würzburger Stein and other vineyards is particularly notable.
• Martin Luther expels theologian Caspar Schwenckfeld from Silesia.
• Paracelsus visits Villach.
• approximate date - The musket is introduced into Japan from Europe.