1634 (MDCXXXIV) was a common year starting on Sunday of the Gregorian calendar and a common year starting on Wednesday of the Julian calendar, the 1634th year of the Common Era (CE) and Anno Domini (AD) designations, the 634th year of the 2nd millennium, the 34th year of the 17th century, and the 5th year of the 1630s decade. As of the start of 1634, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.
|Ab urbe condita||2387|
|Balinese saka calendar||1555–1556|
|English Regnal year||9 Cha. 1 – 10 Cha. 1|
|Chinese calendar||癸酉年 (Water Rooster)|
4330 or 4270
— to —
甲戌年 (Wood Dog)
4331 or 4271
|- Vikram Samvat||1690–1691|
|- Shaka Samvat||1555–1556|
|- Kali Yuga||4734–4735|
|Japanese calendar||Kan'ei 11|
|Julian calendar||Gregorian minus 10 days|
|Minguo calendar||278 before ROC|
|Thai solar calendar||2176–2177|
1760 or 1379 or 607
— to —
1761 or 1380 or 608
|Wikimedia Commons has media related to 1634.|
- February 24–25 – Rebel Scots and Irish soldiers kill Bohemian military leader Albrecht von Wallenstein at Cheb.
- March – Belgian Scientist Jan Baptist van Helmont is interrogated by the Spanish Inquisition and put on house arrest for his experiments regarding Plant Growth.
- March 1 – The Russians vacate their camp, ending the Siege of Smolensk.
- March 25 – Leonard Calvert arrives in Maryland, with Jesuit missionaries Andrew White, John Altham Gravenor, and Thomas Gervase, establishing St. Mary's as the fourth permanent settlement in British North America. In this year they also establish an institution of higher learning there, which later becomes Georgetown University, North America's oldest university.
- June 14 – The Treaty of Polyanovka is signed between the Polish–Lithuanian Commonwealth and the Tsardom of Russia, concluding the Smolensk War.
- July 4 – The city of Trois-Rivières is founded in New France (the modern-day Canadian province of Quebec).
- August (prob.) – Jean Nicolet becomes the first European to set foot in Wisconsin. He is in search of a water-route to the Pacific, when he lands at Green Bay (Lake Michigan).
- August 18 – Urbain Grandier, accused of wizardry, is burned alive in Loudun, France.
- September 5–6 – The Battle of Nördlingen results in a decisive victory for the Army of the Holy Roman Empire and Habsburg Spain.
- September 12 – A gunpowder factory explodes in Valletta, Malta, killing 22 people and damaging several buildings.
- October 11–12 – The Burchardi flood (also known as the second Grote Mandrenke) strikes the North Sea coast of Germany and Denmark, causing 8,000–12,000 deaths.
- November 11 – The Irish House of Commons passes an Act for the Punishment of the Vice of Buggery.
- Curaçao is captured by the Dutch.
- The English establish a settlement at Cochin (modern-day Kochi) on the Malabar Coast.
- Suspecting that Patriarch Afonso Mendes played a part in the Portuguese assault on Mombasa, Emperor Fasilides expels him and several Jesuit missionaries from Ethiopia.
- The Académie Française is formed by Cardinal Richelieu (it will be formally established in 1635).
- The first performance of the Oberammergau Passion Play is held in Bavaria.
- Moses Amyraut's Traité de la predestination is published.
- The Paulaner Brewery is established in Munich, by Minim friars.
- January 1 – Fleetwood Sheppard, English poet (d. 1698)
- January 7
- January 16 – Dorothe Engelbretsdotter, Norway's first professional female author (d. 1716)
- January 25 – Gaspar Fagel, Dutch statesman (d. 1688)
- January 30 – Johann Hugo von Orsbeck, Archbishop-Elector of Trier (d. 1711)
- February 2 – Alfonso IV d'Este, Duke of Modena, Italian noble (d. 1662)
- February 5 – Maria Antonia Scalera Stellini, Italian poet (d. 1704)
- February 6 – George Christian, Prince of East Frisia, prince of Ostfriesland (d. 1665)
- February 7 – Robert Robartes, Viscount Bodmin, English diplomat and politician (d. 1682)
- February 8 – Teodósio, Prince of Brazil, Brazilian prince (d. 1653)
- March 4 – Kazimierz Łyszczyński, Polish philosopher (d. 1689)
- March 11 – Nicholas Gassaway, Colonel, Maryland Provincial Forces (d. 1691)
- March 12 – Cornelis Kick, Dutch painter (d. 1681)
- March 18 – Marie-Madeleine de La Fayette, French novelist (d. 1693)
- March 20 – Balthasar Bekker, Dutch minister and author of philosophical and theological works (d. 1698)
- March 23 – Philip Smythe, 2nd Viscount Strangford, English Member of Parliament (d. 1708)
- March 25 – George Bull, English theologian and Bishop of St David's (d. 1710)
- March 26 – Domenico Freschi, Italian opera composer, Catholic priest (d. 1710)
- March 28 – Sir Richard Temple, 3rd Baronet, English Member of Parliament (d. 1697)
- April 3 – Stanisław Jan Jabłonowski, Polish noble (d. 1702)
- April 8
- John Adolphus, Duke of Schleswig-Holstein-Sonderburg-Plön, German duke (d. 1704)
- Joseph Alleine, English Nonconformist pastor, author (d. 1668)
- April 9 – Countess Albertine Agnes of Nassau, Regent of Friesland, Groningen and Drenthe (1664–1679) (d. 1696)
- April 14 – Sir John Reresby, 2nd Baronet, 17th-century English politician and diarist (d. 1689)
- April 25 – Robert Montagu, 3rd Earl of Manchester, English politician (d. 1683)
- May 4 – Lady Katherine Ferrers, English aristocrat and heiress (d. 1660)
- May 7 – Richard Legh, English politician (d. 1687)
- May 8 – Alexander Stuart, 5th Earl of Moray, Scottish nobleman (d. 1701)
- June 1 – Roeloff Swartwout, American city founder in New York (d. 1715)
- June 6 – Maria Elisabeth of Holstein-Gottorp, Landgravine of Hesse-Darmstadt (d. 1665)
- June 14 – Nathaniel Bond, English politician (d. 1707)
- June 20 – Charles Emmanuel II, Duke of Savoy (d. 1675)
- June 27 – Andreas Cleyer, German physician, pharmacist, botanist, and trader of the Dutch East India Company (d. 1698)
- July 3 – Countess Palatine Dorothea Catherine of Birkenfeld-Bischweiler, Countess of Nassau-Ottweiler (d. 1715)
- July 8 – Thomas Butler, 6th Earl of Ossory (d. 1680)
- July 12 – John George I, Duke of Saxe-Eisenach, German duke (d. 1686)
- July 14 – Pasquier Quesnel, French Jansenist theologian (d. 1719)
- July 18 – Johannes Camphuys, Governor-General of the Dutch East Indies (d. 1695)
- July 23 – Sir John Hoskyns, 2nd Baronet, English politician (d. 1705)
- August 12 – Adam Colonia, Dutch Golden Age painter (d. 1685)
- August 16 – Johann Daniel Major, German professor of theoretical medicine (d. 1693)
- August 24 – Mary Eastey, American witch (d. 1692)
- August 31 – Paul Amman, German physician, botanist (d. 1691)
- September 4 – Robert South, English churchman known for his combative preaching (d. 1716)
- September 6 – Thomas Tryon, British hat maker (d. 1703)
- September 7 – Sir Richard Bulkeley, 1st Baronet, Irish politician (d. 1685)
- September 22 – Christiana of Schleswig-Holstein-Sonderburg-Glücksburg, duchess consort of Saxe-Merseburg (1650–1691) (d. 1701)
- October 10 – Jan van Neck, Dutch painter (d. 1714)
- October 18 – Luca Giordano, Italian late Baroque painter and printmaker in etching (d. 1705)
- November 6 – Giuseppe Ghezzi, Italian painter (d. 1721)
- November 7 – Francis Winnington, Solicitor-General for England and Wales (d. 1700)
- November 23 – Paulet St John, 3rd Earl of Bolingbroke, English politician (d. 1711)
- November 25 – Richard Slater, English politician (d. 1699)
- November 27 – Roger Toothaker, victim of the Salem witch trials (d. 1692)
- November 28 – Marie Luise von Degenfeld, morganatic second wife of Charles I Louis, Elector Palatine of Germany (d. 1677)
- December 15 – Thomas Kingo, Danish bishop (d. 1703)
- December 22 – Mariana of Austria (d. 1696)
- December 31 – Hotta Masatoshi, Japanese rōjū to Shōgun Tokugawa Ietsuna (d. 1684)
- January 17 – Albert Szenczi Molnár, Hungarian translator (b. 1574)
- February 15 – Anna Maria of Ostfriesland, German noblewoman (b. 1601)
- February 25 – Albrecht von Wallenstein, Bohemian general (assassinated) (b. 1583)
- March 23 – Elizabeth Finch, 1st Countess of Winchilsea, English countess (b. 1556)
- April 2 – Maria Celeste, Italian nun, daughter of Galileo Galilei (b. 1600)
- April 8 – Giovanni Srofenaur, Italian musician (b. 1580)
- May 12 – George Chapman, English author (b. c.1559)
- May 15 (bur.) – Hendrick Avercamp, Dutch painter (b. 1585)
- June 22 – Johann von Aldringen, Austrian field marshal (b. 1588)
- June 25 – John Marston, English dramatist (b. 1576)
- July 25 – Francesco de' Medici, Tuscan prince (b. 1614)
- August 9 – William Noy, English jurist (b. 1577)
- August 11 – Frederick Ulrich, Duke of Brunswick-Lüneburg (b. 1591)
- August 18 – Urbain Grandier, French priest (b. 1590)
- September 3 – Edward Coke, English colonial entrepreneur and jurist (b. 1552)
- September 6 – Frederick III, Margrave of Brandenburg-Ansbach (b. 1616)
- September 26 – Dorothea of Anhalt-Zerbst, Duchess of Brunswick-Wolfenbüttel (b. 1607)
- October 6 – Otto Louis of Salm-Kyrburg-Mörchingen, Swedish general in the Thirty Years' War (b. 1597)
- October 8 – Francis Julius of Saxe-Lauenburg, Prince (b. 1584)
- October 19 – Agnes of Jesus, French Catholic nun (b. 1602)
- November 14 – Sophia of Holstein-Gottorp, Regent of Mecklenburg-Schwerin (1603–1608) (b. 1569)
- November 19 – Alexander Charles Vasa, 5th son of King Sigismund III Vasa (b. 1614)
- November 20 – Anna Maria of Solms-Sonnewalde, Countess consort of Hohenlohe-Langenburg (b. 1585)
- December 11 – Fadrique de Toledo, 1st Marquis of Villanueva de Valdueza, Spanish noble and admiral (b. 1580)
- December 25 – Lettice Knollys, English noblewoman (b. 1543)
- December 29 – John Albert Vasa, Polish bishop (b. 1612)
- date unknown