January 18, 1520 – King Christian II of Denmark and Norway defeats the Swedes at Lake Åsunden.

January 19, 1520 – Sten Sture the Younger, the Regent of Sweden, is mortally wounded at the Battle of Bogesund.

June 15, 1520 – Pope Leo X threatens to excommunicate Martin Luther in papal bull Exsurge Domine.

October 21, 1520 – João Álvares Fagundes discovers the islands of Saint-Pierre and Miquelon, bestowing them their original name of “Islands of the 11,000 Virgins”.

November 8, 1520 – Stockholm Bloodbath begins: A successful invasion of Sweden by Danish forces results in the execution of around 100 people.

November 9, 1520 – More than 50 people are sentenced and executed in the Stockholm Bloodbath

November 10, 1520 – Danish King Christian II executes dozens of people in the Stockholm Bloodbath after a successful invasion of Sweden.

November 28, 1520 – After navigating through a strait at the southern end of South America, three ships under the command of Portuguese explorer Ferdinand Magellan reach the Pacific Ocean, becoming the first Europeans to sail from the Atlantic Ocean to the Pacific.

December 10, 1520 – Martin Luther burns his copy of the papal bull Exsurge Domine outside Wittenberg’s Elster Gate.

March 3, 1520 – Matthias Flacius, Croatian Protestant reformer (d. 1575)

August 10, 1520 – Madeleine of Valois, French-born Queen consort of the Scots, wife of James V of Scotland (d. 1537)

October 5, 1520 – Alessandro Farnese, Italian cardinal (d. 1589)