1621 CE

The Pilgrims of Plymouth Colony sign a peace treaty with Massasoit of the Wampanoags. The Mayflower sets sail from Plymouth, on a return trip to England. The city of Tornio in Lapland is founded by King Gustavus Adolphus of Sweden, becoming the northernmost city in the world at the time.

Geopolitics & Diplomacy

February 17 – Myles Standish is appointed as the first commander of Plymouth Colony.source
March 22 – The Pilgrims of Plymouth Colony sign a peace treaty with Massasoit of the Wampanoags.source
March 31 – King Philip IV of Spain begins his 44-year rule.source
October 9 – The Treaty of Khotyn is signed between the Ottoman Empire and the Polish–Lithuanian Commonwealth, ending the First Polish-Ottoman War.source
November 11 – The ship Fortune arrives at Plymouth Colony, with 35 more settlers.source
December 31 – Thirty Years' War: The Peace of Nikolsburg is signed between Ferdinand II, Holy Roman Emperor and Gabor Bethlen, Prince of Transylvania. Bethlen agrees to renounce his claims to Hungary. In return Bethlen receives several counties and lands along the eastern border of the Holy Roman Empire, and Moravia is granted religious freedom.source

Conflict & Security

January 18 – The Dutch East India Company formally names its fortress at Jayakarta in Indonesia, calling it Batavia. Upon the independence of the Dutch East Indies as Indonesia in 1945, Batavia will be renamed Jakarta.source
January 22 – The Tianqi era begins in Ming Dynasty China, six months after Zhu Changluo becomes the Taichang Emperor.source
April 9 – The Twelve Years' Truce between the Dutch Republic and the Spanish Empire expires, and both sides prepare to resume the Eighty Years' War.source
June 21 – Thirty Years' War: Twenty-seven Czech lords are executed on the Old Town Square in Prague, as a consequence of the Battle of White Mountain.source
June 24 – Huguenot rebellions: Saint-Jean-d'Angély is taken, after a 26-day siege by Royal forces.source
July 25 – Thirty Years' War – Battle of Neu Titschein: Remnants of the Bohemian army temporarily hold off the Imperial advance in Silesia.source
August 8 – Huguenot rebellions: The French Protestant city of La Rochelle joins in the revolt by Benjamin, Duke of Soubise.source
August 22 – Huguenot rebellions: Louis XIII besieges the city of Montauban, but is forced to abandon the battle by November 9.source
September 2 – The Battle of Khotyn begins as a force of more than 120,000 Ottoman troops attacks the Moldavian city of Khotyn. Despite the Ottomans' numerical superiority, the Polish-Lithuanian Commonwealth wins the battle and forces a surrender five weeks later.source
The Swedish city of Gothenburg is founded by King Gustavus Adolphus of Sweden. The king also grants city rights to Luleå, Piteå and Torneå (Tornio). Riga falls under the rule of Sweden.source
The Dutch East India Company sends 2,000 soldiers, under the command of Jan Pieterszoon Coen, to the Banda Islands, in order to force the local inhabitants to accept the Dutch trade monopoly on the lucrative nutmeg, grown almost exclusively on those islands. The soldiers proceed to massacre most of the 15,000 indigenous inhabitants.source
Tamblot rallies an unknown, large number of people in Bohol, Captaincy General of the Philippines to revolt against the Spanish Empire.source

Exploration & Expansion

March 16 – Samoset, a Mohegan, visits the settlers of Plymouth Colony and greets them: "Welcome, Englishmen! My name is Samoset."source
April 1 – The Plymouth, Massachusetts colonists create the first treaty with native Americans.source
April 5 – The Mayflower sets sail from Plymouth, on a return trip to England.source
May 12 – The city of Tornio in Lapland is founded by King Gustavus Adolphus of Sweden, becoming the northernmost city in the world at the time.source
The Venezuelan city of Petare is founded by Spanish conquistadors, as San Jose de Guanarito.source

Religion & Belief

January 29 – Ferdinand II, Holy Roman Emperor, declares the Elector of the Palatinate, Frederick V, to be a traitor to the Empire.source
February 9 – Papal Conclave of 1621: Pope Gregory XV succeeds Pope Paul V, as the 234th pope.source
May 24 – The Protestant Union is formally dissolved.source

Economy & Finance

June 3 – The Dutch West India Company is founded.source

Science & Discovery

December – The Dutch mathematician and astronomer, Willebrord Snel van Royen (1580–1626), reveals he has rediscovered the law of refraction, also known as Snellius' law.source

Crime & Justice

January 12 – Şehzade Mehmed, the 15-year old half-brother of Ottoman Sultan Osman II, is put to death by hanging on Osman's orders. Before dying, Mehmed prays aloud that Osman's reign as Sultan be ruined.source
January 24 – Twelve days after the murder of Prince Mehmed on orders of Sultan Osman II, Constantinople is hit by bitter winter weather, leading to rioting by persons who believe that the punishment of Osman is the will of Allah.source

Climate & Environment

May 2 – The Panama earthquake affects the Isthmus of Panama, with an estimated magnitude of 6.9, and a maximum Mercalli intensity of VII.source

Culture & Society

October 9 (September 29 O.S.) – The Pilgrims of Plymouth Colony and Wampanoags celebrate a harvest feast (three days), later regarded as the First Thanksgiving, noted for the temporary peace between the English and the local Indians. The celebration is believed by later historians to have coincided with Michaelmas, observed on September 29 by the Anglican Communion on the calendar used in England at the time.source

Births

January 27 – Thomas Willis, English doctor who played an important part in the history of anatomy (d. 1675)source
February 21 – Rebecca Nurse, Massachusetts colonist, executed as a witch (d. 1692)source
February – Lamoral II Claudius Franz, Count of Thurn and Taxis, Postmaster General of the Holy Roman Empire (1646–1676) (d. 1676)source
March 31 – Andrew Marvell, English metaphysical poet and politician (d. 1678)source
April 1 – Guru Tegh Bahadur, 9th Sikh Guru (d. 1675)source
April 25 – Roger Boyle, 1st Earl of Orrery, Anglo-Irish soldier, statesman and dramatist (d. 1679)source
June 2 – Rutger von Ascheberg, Courland-born soldier in Swedish service (d. 1693)source
July 8 – Jean de La Fontaine, French writer (d. 1695)source
July 8 – Leonora Christina Ulfeldt, Danish countess and author (d. 1698)source
July 22 – Thomas Hanford, New England settler, Puritan minister (d. 1693)source
October 29 – The London Pageant of 1621 celebrates the inauguration of Edward Barkham (Lord Mayor).source
November 15 – Henry Mordaunt, 2nd Earl of Peterborough, English diplomat (d. 1697)source
December 23 – Edmund Berry Godfrey, English magistrate whose mysterious death caused anti-Catholic uproar in England (d. 1678)source
December 23 – Heneage Finch, 1st Earl of Nottingham, English politician (d. 1682)source

Deaths

February 10 – Pietro Aldobrandini, Italian cardinal, patron of the arts (b. 1571)source
March 4 – Ana de Jesús, Spanish Discalced Carmelite nun, spiritual writer and Servant of God (b. 1545)source
June 8 – Anne de Xainctonge, French Roman Catholic nun (b. 1567)source
June 21 – Kryštof Harant z Polžic a Bezdružic, Bohemian composer, soldier and author (executed) (b. 1564)source
July 2 – Thomas Harriot, English astronomer and mathematician (b. c. 1560)source
August 3 – Anna Juliana Gonzaga, Archduchess of Austria and nun (b. 1566)source
August 13 – John Berchmans, Belgian Jesuit scholastic and saint (b. 1599)source
August 30 – Bahāʾ al-dīn al-ʿĀmilī, one of the main co-founders of Isfahan School of Islamic Philosophy (b. 1547)source
September 17 – Robert Bellarmine, Italian Roman Catholic bishop, saint, proponent of futurism (b. 1542)source
September 25 – Mary Sidney, English writer, patroness and translator (b. 1561)source
October 8 – Antoine de Montchrestien, French dramatist and economist (b. c. 1575)source
October 16 – Jan Pieterszoon Sweelinck, Dutch composer (b. 1562)source
December 13 – Katarina Stenbock, queen of Gustav I of Sweden (b. 1535)source
December 15 – Charles d'Albert, duc de Luynes, Constable of France (b. 1578)source