1580
1580 was a leap year starting on Friday of the Julian calendar.
Events
January–March
- January 31 - Portuguese succession crisis of 1580: The death of Henry, King of Portugal, with no direct heirs, leads to conflict between his potential successors, including King Philip II of Spain and Infanta Catherine, Duchess of Braganza.
- February 16 - The massacre of 20 artists at the Mardi Gras festivities, at the annual Carnaval de Romans during the festival, takes place in France at Romans-sur-Isère.
- February 28 - Three Jesuit priests from Portuguese Goa, including Rodolfo Acquaviva, arrive in Agra on the mainland of India as guests of the Mughal Emperor, Akbar the Great, who is curious about Christianity. The Emperor grants land to the Jesuit fathers for the building of the first Roman Catholic Church in the Mughal Empire.
- March 1 - Michel de Montaigne signs the preface to his most significant work, Essays. They are published later this year.
- March 3 - George de Lalaing, Count of Rennenberg defects from the Union of Utrecht and the Dutch Republic, and turns over the province of Groningen to King Philip II of Spain.
- March 25 - Iberian Union: King Philip II of Spain becomes King of Portugal under the name Philip I, following the death without heirs of King Henry of Portugal, in a personal union of the crowns, thus maintaining Portuguese independence. The Philippine Dynasty rule lasts until 1640.
April–June
- April 6 - The Dover Straits earthquake occurs.
- April 9 - English Fury at Mechelen: English and Scottish mercenaries, assisting the Dutch Republic, storm the Spanish Netherlands city of Mechelen, killing 60 civilians and plundering the town's houses and churches.
- May 29 - Stephen Báthory is formally crowned as Grand Duke of Lithuania at the Vilnius Cathedral.
- May - The Lipizzan stud is established by Charles II, Archduke of Austria.
- June 5 - In the Kingdom of Golconda, 15-year-old Muhammad Quli Qutb Shah is proclaimed as the new Sultan upon the death of his father, Ibrahim Quli Qutb Shah Wali.
- June 9 - Rebels of the Dutch Union of Utrecht, aided by French soldiers, make a surprise attack on the Spanish Netherlands city of Diest in the Duchy of Brabant, and overwhelm the strategic location, now in Belgium, in one day.
- June 11 - Within the Viceroyalty of Peru in South America Spanish explorer Juan de Garay founds the first permanent Spanish settlement at what is now the capital of Argentina, on the Rio de la Plata. Garay, who came on an expedition down the Paraná River from Asunción, arrives at the site of the failed Spanish settlement of Ciudad de Nuestra Señora Santa María del Buen Ayre, that had been created by Pedro de Mendoza in 1536 and abandoned in 1542. Garay names the new settlement "Santísima Trinidad" but the city eventually takes the name of the port, which he calls "Puerto de Santa María de los Buenos Aires."
- June 21 - England signs a commercial treaty with the Ottoman Empire, and Sultan Murad III sends a letter to Queen Elizabeth I informing her, "Just as the merchants of Poland and France and Venice come and go, the merchants of your domain also shall bring wares to our Well-Protected Domains and take away wares." In return, Murad III is able to purchase English metals for his war with Persia.
- June 25 - The Book of Concord, a collection of Lutheran confessional documents, is published.
July–September
- July 12 - The Ostrog Bible, the first complete printed Bible translation into a Slavic language, is first printed at Ostroh in the Polish–Lithuanian Commonwealth by Ivan Fyodorov.
- July 24 - Portuguese succession crisis of 1580: António, Prior of Crato, a grandson of the late King Manuel by Manuel's second son, the Duke of Beja is proclaimed King of Portugal by his supporters in the city of Santarém, and popular acclamation follows in Lisbon and other locations. Portugal's parliament, the Cortes, refuses to acknowledge Antonio and he is defeated 32 days later at Alcântara.
- August 25 - Battle of Alcântara: Spanish armies, led by Fernando Álvarez de Toledo, defending the claim of King Philip II of Spain to the Portuguese throne, defeat the armies of Portuguese claimant António, Prior of Crato.
- September 26 - Francis Drake returns to Plymouth, England from his voyage of circumnavigation on the Golden Hind, the second completed in a continuous voyage, and the first under its original commander.
- September 29 - Five of the seven provinces of the Dutch Republic sign the Treaty of Plessis-les-Tours, recognizing Francis, Duke of Anjou as the Republic's sovereign.
October–December
- October 4 - Lorenzo Suárez de Mendoza, the Spanish Count of Coruña, arrives in Mexico City to take office as the Viceroy of New Spain, administering Mexico and Central America on behalf of King Philip II.
- October 15 - King Bayinnaung of Bruma dispatches a naval force of 200 ships and 8,000 soldiers to invade the Kingdom of Mrauk U, but the attempt fails after a year. Burmese troops are ordered withdrawn after Bayinnaung dies and is succeeded by his son Nanda Bayin.
- October 18 - The Siege of Steenwijk in the Dutch Republic is started by the Spanish Netherlands. The siege will last four months and the Spanish troops will capture Steenwijk on February 23.
- October 24 - The War of the Portuguese Succession comes to an end as Spanish forces crush the final Portuguese resistance in the last stronghold in mainland Portugal, Porto. For the next 60 years, Portugal will be ruled by the Kings of Spain.
- November 10 - Second Desmond Rebellion: The Siege of Smerwick ends after three days when their commander surrenders to the English. Members of a group of at least 400 freelance soldiers, and perhaps as many as 700, for the Papal States are summarily executed on orders of the English Lord Deputy of Ireland, Baron Grey de Wilton.
- December 31 - James Douglas, 4th Earl of Morton, formerly the regent for King James VI of Scotland, is arrested during a meeting of Scotland's Privy Council at Holyrood on the accusation of James Stewart, Earl of Arran that the Earl of Morton had participated in the 1567 murder of Lord Darnley, husband of Mary, Queen of Scots and father of King James. Morton is taken to Dumbarton Castle and convicted of conspiracy to murder, and executed on June 2.
Date unknown
- The Billy Mitchell volcano, on the island of Bougainville, undergoes a catastrophic eruption.
- The first session of the Jewish Vaad is held in Lublin, Poland; 70 delegates of Jewish local qahals meet to discuss taxation, and other issues important to Jewish communities.
- The Old City of Zamość is established in Poland, by Jan Zamoyski.
- The 1580 influenza pandemic sweeps the world, starting in Asia and moving rapidly through Africa, Europe, and eventually the Americas. More than 10% of the population of Rome dies, and whole towns in Spain are depopulated.