1521
1521 was a common year starting on Tuesday of the Julian calendar, the 1521st year of the Common Era and Anno Domini designations, the 521st year of the 2nd millennium, the 21st year of the 16th century, and the 2nd year of the 1520s decade.
Events
January–March
- January 3 - Pope Leo X excommunicates Martin Luther, in the papal bull Decet Romanum Pontificem.
- January 22 - Charles V, Holy Roman Emperor, opens the Diet of Worms in Worms, Germany.
- January 27 - Suleiman the Magnificent suppresses a revolt by the ruler of Damascus, Janbirdi al-Ghazali.
- February 2 - The Nydala Abbey Bloodbath takes place at Nydala Abbey, Sweden; the abbot and many monks are murdered by Danes.
- March 6
- * Ferdinand Magellan makes the first European contact with Guam, most likely landing in Tumon.
- * Martin Luther is summoned to appear before the Diet of Worms.
- March 16 - Ferdinand Magellan reaches the Philippines, in eastern Samar.
- March 31 - The First Mass in the Philippines is held.
April–June
- April 7
- * Ferdinand Magellan arrives at Cebu.
- * Martin Luther preaches an inflammatory sermon to students at Erfurt, while on his way to Worms.
- April 16-18 - Martin Luther is examined before Emperor Charles V and the Diet of Worms, where he refuses to recant his writings and allegedly proclaims, "Here I stand", regarding his belief in the Bible alone, as the standard of Christian doctrine.
- April 23 - Revolt of the Comuneros - Battle of Villalar: Castilian royalists defeat the rebels. Juan López de Padilla, Francisco Maldonado, and Juan Bravo are executed the following day as the leaders of the rebels.
- April 26 - Martin Luther leaves Worms and disappears for around a year - he is rumored to be murdered, but is actually in hiding at the Wartburg castle.
- April 27 - Battle of Mactan: Ferdinand Magellan is killed in the Philippines when he confronts Lapulapu, the chief of the island.
- April or May - Battle of Tunmen in Tuen Mun : The Ming Dynasty navy defeats the Portuguese navy.
- May 17 - Edward Stafford, 3rd Duke of Buckingham, is executed for treason in Tower Hill.
- May 20 - At the Battle of Pampeluna in Italy, and alliance of forces from French and the Kingdom of Navarre forces defeat those of Spain.
- May 25 - The Diet of Worms ends when Charles V, Holy Roman Emperor issues the Edict of Worms, declaring Martin Luther an outlaw and banning his literature.
- May 27 - After death of his cousin, Jiajing, Prince Zhu Houcong became the new Ming dynasty Emperor of China, taking the imperial name of the Emperor Jiajing becomes the new.
- June 25 - Suleiman the Magnificent begins the siege of Belgrade.
- June 29 or 30 - The oldest surviving dateable document written primarily in the Romanian language: Neacșu's letter, written by a trader from Câmpulung, to Johannes Benkner, the mayor of Brașov, warning that the Ottoman Empire is preparing its troops to cross into Wallachia and Transylvania; the script used is Romanian Cyrillic.
- June 30 - Battle of Esquiroz: French forces under André de Foix, fighting for the exiled King of Navarre Henri d'Albret, are defeated by the Spanish, and forced to abandon their attempt to recover Henri's kingdom.
July–September
- July 15 — San Juan Bautista is founded as the new capital of the archipelago of Puerto Rico.
- August 13 - Fall of Tenochtitlan: Cuauhtémoc surrenders to Cortés, thus incorporating the Aztec Empire into the Spanish Empire and ending the Late Postclassic period in Mesoamerica.
- August 20 - The Italian War of 1521–1526 breaks out between Charles V, Holy Roman Emperor, and Francis I of France as Henry III of Nassau-Breda leads Imperial troops on an invasion of northeastern France.
- August 29 - Belgrade is captured by the Ottoman army of Suleiman the Magnificent.
- September 12 – In the Italian War, the Holy Roman Empire abandons its siege of the French-controlled city of Parma after 17 days.
- September 15
- * Gazi Husrev Bey replaces Bali-beg Jahjapašić as the Ottoman Governor of Bosnia.
- * Teodosie becomes the new Voivode of Wallachia, at the capital, Targoviste, now in Romania.
October–December
- October 25 - The Revolt of the Comuneros, an uprising by citizens of the Kingdom of Castile against the rule of Spain's King Carlos I, ends as the comuneros surrender Toledo.
- November 23 - Spanish–German–Papal forces under Prospero Colonna force French Marshal Odet de Lautrec to abandon Milan.
- December 27 - The Zwickau prophets arrive in Wittenberg, disturbing the peace and spreading the idea of rejecting infant baptism.
Date unknown
- Jacopo Berengario da Carpi publishes Commentaria cum amplissimus additionibus super anatomiam Mundini in Bologna, including observation of the vermiform appendix.
- The Grand Duchy of Ryazan is annexed by the Grand Duchy of Moscow.