1544

January–March

• January 4 - In India, Maldeo Rathore, King of Marwar is tricked by counterintelligence spread by Mughal Emperor and Afghan Shah Sher Shah Suri into departing from Jodhpur. The Battle of Sammel begins shortly afterward and is won by the Afghan and Mughal armies.
• January 13 - At Västerås, the estates of Sweden swear loyalty to King Gustav Vasa and to his heirs, ending the traditional electoral monarchy in Sweden. Gustav subsequently signs an alliance with the Kingdom of France.
• January 24 - During a solar eclipse visible over the Netherlands, Dutch mathematician and designer Gemma Frisius makes the first recorded use of a camera obscura and uses it to observe the event without directly looking at the Sun. Frisius writes about the event the next year and illustrates it in his book De Radio Astronomica et Geometrica.
• February 20 - The Fourth Diet of Speyer is convened.
• March 7 - Five Roman Catholic priests— John Larke, John Ireland, the vicar of Eltham and Robert Singleton are executed at Tyburn, outside of London, in England after being convicted of participating in the Prebendaries' Plot to remove Thomas Cranmer, the Protestant Archbishop of Canterbury.
• March 16 -
• *The Battle of Glasgow is fought for control of Scotland between Matthew Stewart, 4th Earl of Lennox and the troops of the Regent, James Hamilton, 2nd Earl of Arran
• *Friedrich II becomes the new Elector Palatine of Germany's Rhineland within the Holy Roman Empire upon the death of his brother Ludwig V at Heidelberg.
• March 29 - Royal assent is given by King Henry VIII to laws passed by the English Parliament, including the Third Succession Act, the amended Treason Act and the King's Style Act.

  April–June

• April 11 - Battle of Ceresole: French forces under the Comte d'Enghien defeat forces of the Holy Roman Empire, under the Marques Del Vasto, near Turin.
• April 21 - The Italian town of Agropoli, frequently targeted by pirates from North Africa, is sacked by Ottoman raiders and 100 people are taken prisoner.
• May 3 - Edward Seymour, Earl of Hertford, with an English army, captures Leith and Edinburgh from the Kingdom of Scotland.
• May 7 - Edward Seymour, Lord Hertford, carries out the burning of Edinburgh, capital of the Kingdom of Scotland, by the English Navy, then proceeds to destroy neighboring areas.
• May 17 - At Lima, Blasco Núñez Vela takes office as the first Spanish Governor of the Viceroyalty of Peru, which encompasses most of what are now the nations of Peru, Ecuador, Bolivia, Paraguay and Uruguay, as well as the western part of Brazil.
• May 23 -
• *The Treaty of Speyer is signed between the Holy Roman Empire and the Kingdom of Denmark. Charles V, Holy Roman Emperor agrees to recognize Christian III as the ruler of Denmark and Norway, and abandons further attempts to restore King Christian II to the throne. In return, Denmark and Norway agree to support the Habsburg monarchy in the Empire.
• *The allied French and Ottoman navies depart from the French port of Marseille and travel to Constantinople, the Ottoman capital. The French fleet is commanded by Antoine Escalin des Aimars, known as Captain Polin, French ambassador to the Ottomans, while the Turks are led by Hayreddin Barbarossa.
• May 25 - On orders of King Henry VIII, the English Navy, commanded by Thomas Howard, 3rd Duke of Norfolk, begins crossing the English Channel to invade from the west with 19,000 troops, while Charles V, Holy Roman Emperor, commences an invasion of France from the east.
• June 4 - A combined force of troops from the Holy Roman Empire and from Spain, both commanded by Emperor Charles V, defeat the French in the Battle of Serravalle after three days of fighting.
• June 8 - The Duke of Norfolk crosses the English Channel after having landed troops in Normandy.
• June 24 - The plundering of the Italian island of Ischia, part of the Kingdom of Naples is carried out by the Ottoman Empire Navy, commanded by Hayreddin Barbarossa, who captures 4,000 of the residents and then sells them as slaves in Algeria.

  July–September

• July 10- Troops of the Holy Roman Empire begin the six-week siege of Saint-Dizier in eastern France.
• July 15 - Battle of the Shirts: The Clan Fraser of Lovat and Macdonalds of Clan Ranald fight over a disputed chiefship in Scotland; reportedly, five Frasers and eight or ten Macdonalds survive.
• July 19- Italian War of 1542–46: King Henry VIII of England begins the siege of the city of Boulogne in northern France and continues for almost two months before the city surrenders.
• July 20 - Albert, Duke of Prussia signs a deed granting land for creation of the University of Königsberg.
• August 17 -
• * The University of Königsberg is inaugurated in Prussia.
• * In France, Saint-Dizier surrenders to the Holy Roman Empire after a siege of more than a month.
• September 14 - The siege of Boulogne ends as the city surrenders to King Henry VIII.
• September 18
• *Peace of Crépy: Peace is declared between Charles V, Holy Roman Emperor, and Francis I of France. The war between France and England continues.
• * The expedition of Juan Bautista Pastene makes landfall in San Pedro Bay, southern Chile, claiming the territory for Spain.
• September 22 - Captain Juan Bautista Pastene leads the first European expedition to the estuary of Valdivia, Chile and Corral Bay.

  October–December

• October 9 - Second Siege of Boulogne: French forces under the Dauphin assault Boulogne, but are ultimately unsuccessful.
• November 24 - Rüstem Opuković Pasha, son-in-law of the Sultan Suleiman the Magnificent, is appointed as the new Grand Vizier of the Ottoman Empire, replacing Hadım Suleiman Pasha.
• December 9 - Crown Prince Yi Ho becomes the new King of Korea upon the death of his father, King Joseon. Yi Ho reigns for eight months before being poisoned by his own mother, and is posthumously named as King Injong of Joseon.

  Date unknown

• Mongols, led by Anda, burn the suburbs of Peking in China.
• After being asked by Cosimo I de' Medici, Grand Duke of Tuscany, botanist Luca Ghini comes to the University of Pisa as the chair of botany, where he had the year prior established the Orto botanico di Pisa.
• Rats make their first appearance in South America, arriving in Peru with the species black rat.
• Portuguese explorers encounter the island of Taiwan, and call it Ilha Formosa.