* 1521 – Tenochtitlan ( present day Mexico City ) falls to conquistador Hernán Cortés.

* 1521 – Martin Luther's first appearance before the Diet of Worms to be examined by the Holy Roman Emperor Charles V and the other estates of the empire.

Category: People of the Polish – Teutonic War 1519 – 1521 ( German side )

* 1521 – The Ottoman Turks occupy Belgrade.

* 1521 – The Ottoman Turks capture Nándorfehérvár, now known as Belgrade.

* 1521 – Trial of Martin Luther begins its second day during the assembly of the Diet of Worms.

* 1521 – Battle of Villalar: King Charles I of Spain defeats the Comuneros.

* 1521 – Trial of Martin Luther over his teachings begins during the assembly of the Diet of Worms.

* 1521 – Zhengde Emperor of China ( b. 1491 )

* 1521 – Ferdinand Magellan, Portuguese explorer ( b. 1480 )

* 1521 – Pope Urban VII ( d. 1590 )

* 1521 – Ferdinand Magellan arrives at Cebu.

A fishing colony was established on the island about 1521 – 22 by the Portuguese under João Álvares Fagundes.

Cuauhtémoc ( also known as Cuauhtemotzin, Guatimozin or Guatemoc ; c. 1495 – 28 February 1525 ) was the Aztec ruler ( tlatoani ) of Tenochtitlan from 1520 to 1521.

* 1521 – Takeda Shingen, Japanese warlord ( d. 1573 )

* 1521 – Pope Leo X ( b. 1475 )

* 1475 – Pope Leo X ( d. 1521 )

* 1597 – Petrus Canisius, Dutch Jesuit ( b. 1521 )

* 1521 – Pope Sixtus V ( d. 1590 )

* 1521 – Manuel I of Portugal ( b. 1469 )

The only pre-Columbian North American rulers to be commonly called emperors were the Hueyi Tlatoani of the Aztec Empire ( 1375 – 1521 ).

* Sebastian Brant ( 1457 – 1521 )

* 1521 – Pope Leo X excommunicates Martin Luther in the papal bull Decet Romanum Pontificem.

* 1521 – Spanish forces defeat a combined French and Navarrese army at the Battle of Noáin during the Spanish conquest of Iberian Navarre.

* 1521 – Battle of Pampeluna: Ignatius Loyola is seriously wounded.

A notable wielder of the kampílan was Datu Lapu-Lapu, the Muslim king of Mactan and his warriors who defeated the Spaniards and killed Portuguese explorer Ferdinand Magellan at the Battle of Mactan on 27 April 1521.

April 23 is designated Castile and León Day, commemorating the defeat of the comuneros at the Battle of Villalar during the Revolt of the Comuneros, in 1521.

The French and Navarrese invaded Spanish Navarre, but were ultimately expelled by Charles after the Battle of Noain ( June 1521 ).

In 1521, Ferdinand Magellan was killed in Cebu at the Battle of Mactan by the forces of Raja Lapu-Lapu, the Mactan tribal chief.

The Battle of Mactan on April 27, 1521, is celebrated as the earliest reported resistance of the natives in the Philippines against foreign invaders.

The Battle of Mactan (), (), was fought in the Philippines on April 27, 1521.

The Battle of Pavia, fought on the morning of 24 February 1525, was the decisive engagement of the Italian War of 1521 – 26.

The French, in possession of Lombardy at the start of the Italian War of 1521 – 26, had been forced to abandon it after their defeat at the Battle of Bicocca in 1522.

On the morning of April 27, 1521, Lapu-Lapu led 1, 500 Mactan warriors armed with barong, spears, kampilan, and kalasag, in a battle against Portuguese explorer and conquistador Ferdinand Magellan who led a force of forty-nine Spanish soldiers armed with guns in what would later be known as the Battle of Mactan.

In 1521 he succeeded in defending the duchy against the Spanish army, but in 1522 he was completely defeated at the Battle of Bicocca, and was forced to evacuate the Milanese.

But the Revolt was defeated at almost the same time as the invasion, and Asparros faced a huge and united Castilian army at the Battle of Noáin on 30 June 1521.

A notable wielder of the kampílan was Datu Lapu-Lapu ( the king of Mactan ) and his warriors, who defeated the Spaniards and killed Portuguese explorer Ferdinand Magellan at the Battle of Mactan on April 27, 1521.

In 1521, 132 years after the Battle of Kosovo, the fortress, like most parts of the Serbian state, was conquered by the Turks and remained ( with short periods of the Austrian and Serbian occupation ), under the rule of the Ottoman Empire until the year 1867 when the Turks withdrew from Belgrade and Serbia.

The Genoese Pilot of the Magellan expedition, states — wrongly — in his eyewitness account that the Spaniards had no interpreter when they arrived back to Cebu, because Enrique had died on Mactan along with Magellan during the Battle of Mactan in 1521.

After the Battle of Marignano, drawing by Urs Graf, 1521

* Battle of Fuenterrabía ( 1521 ), in which Claude, Duke of Guise distinguished himself, was instigated by Guillaume Gouffier, seigneur de Bonnivet, in command of the army of Navarre ; he occupied Fuenterrabía and was probably responsible for the renewal of hostilities resulting from its not being restored.

* First Battle of Tamao ( 1521 )

According to Antonio Pigafetta's account, after Magellan's death on April 21, 1521 at the Battle of Mactan ( Philippines ), Duarte Barbosa, one of the few survivors of the battle, was made co-commander of the expedition along with João Serrão.

However in 1521, after nearly a year of rebellion, the reorganized supporters of the emperor Charles V struck a crippling blow to the comuneros at the Battle of Villalar, and finally royal troops of the Count of Haro captured Tordesillas.

His successor, Suleiman the Magnificent, further expanded the conquests after capturing Belgrade in 1521 and using its territorial base to conquer Hungary, and other Central European territories, after his victory in the Battle of Mohács as well as also pushing the frontiers of the empire to the east.

Magellan's sword-wielding conquistadors fell to Datu Lapu-Lapu who used Eskrima to defeat the Spaniards at the Battle of Mactan, April 27, 1521.