|Centuries:||16th century – 17th century – 18th century|
|Decades:||1590s 1600s 1610s – 1620s – 1630s 1640s 1650s|
|Years:||1620 1621 1622 – 1623 – 1624 1625 1626|
|1623 by topic:|
|Arts and Science|
|Architecture - Art - Literature - Music - Science|
|Lists of leaders|
|Colonial governors - State leaders|
|Birth and death categories|
|Births - Deaths|
|Establishments and disestablishments categories|
|Establishments - Disestablishments|
|Ab urbe condita||2376|
|English Regnal year||20 Ja. 1 – 21 Ja. 1|
|Chinese calendar||壬戌年 (Water Dog)
4319 or 4259
— to —
癸亥年 (Water Pig)
4320 or 4260
|- Vikram Samvat||1679–1680|
|- Shaka Samvat||1545–1546|
|- Kali Yuga||4724–4725|
|Japanese calendar||Genna 9
|Julian calendar||Gregorian minus 10 days|
|Minguo calendar||289 before ROC
|Thai solar calendar||2165–2166|
|Wikimedia Commons has media related to 1623.|
1623 (MDCXXIII) was a common year starting on Sunday (dominical letter A) of the Gregorian calendar and a common year starting on Wednesday (dominical letter E) of the Julian calendar, the 1623rd year of the Common Era (CE) and Anno Domini (AD) designations, the 623rd year of the 2nd millennium, the 23rd year of the 17th century, and the 4th year of the 1620s decade. Note that the Julian day for 1623 is 10 calendar days difference, which continued to be used from 1582 until the complete conversion of the Gregorian calendar was entirely done in 1929.
- February – France, Savoy, and Venice sign the Treaty of Paris, agreeing to cooperate in removing Spanish forces from the strategic Alpine pass of Valtelline.
- February 25 – Thirty Years' War: Duke Maximilian I of Bavaria becomes Elector of the Electorate of the Palatinate.
- March 5 – The first American temperance law is enacted, in Virginia.
- March 9 – Amboyna massacre: Ten men in the service of the British East India Company, nine Japanese and one Portuguese, are executed by the Dutch East India Company.
- March 20 – Richard Frethorne begins writing a letter to his parents from Jamestown, Virginia.
- April 11 – King Gwanghaegun of Joseon is deposed in a coup. He is succeeded by King Injo.
- April 29 – A fleet of 11 Dutch ships depart for the coast of Peru, seeking to seize Spanish treasure.
- June 14 – The first breach-of-promise lawsuit: Rev. Gerville Pooley, in Virginia, files against Cicely Jordan, but loses. 
- June 29 – Première of Pedro Calderón de la Barca's first play, Amor, honor y poder, at the Court of Habsburg Spain.
- July – The ship Anne arrives from England at "New Plymouth" (Plymouth Colony), carrying more settlers, followed a week or two later by the Little James.
- August 6
- Papal Conclave of 1623: Pope Urban VIII (Maffeo Barberini) succeeds Pope Gregory XV as the 235th pope.
- Thirty Years' War: Chased by the Count of Tilly's army, Christian of Brunswick's army attempts to flee to the Dutch Republic. Tilly's army catches Brunswick five miles from the border. In the resulting Battle of Stadtlohn, Christian's army is destroyed.
- September 10 – Murat IV (1623–1640) succeeds Mustafa I (1622–1623) as Ottoman Emperor.
- November 1 – Fire at Plymouth Colony destroys several buildings.
- Between November 8 and early November – Publication in London of the "First Folio" (Mr. William Shakespeares Comedies, Histories, & Tragedies), a collection of 36 of the plays of Shakespeare, half of which have not previously been printed.
- The Safavids recapture Baghdad.
- England first colonizes Saint Kitts and Nevis.
- Wilhelm Schickard invents his "Calculating Clock", an early mechanical calculator.
- Zildjian begins the commercial manufacture of cymbals in Turkey. The company will still be operating, from Massachusetts, in the 21st century.
- Procopius' long-lost Secret History is rediscovered in the Vatican Library.
- Giambattista Marini publishes his long poem Adone.
- Tommaso Campanella publishes The City of the Sun.
- Johannes Rudbeck founds Rudbeckianska Gymnasiet, the first gymnasium in Sweden.
- The second Thanksgiving is celebrated at Plymouth Plantation.
- Erotomania is first mentioned in a psychiatric treatise.
- On the coast of Massachusetts Bay, the settlement that will become the City of Gloucester, Massachusetts is first inhabited by men from Dorchester, England.
- On the coast of New Hampshire, the settlement of Hilton's Point that will become Dover is established by men from London, England, the first European settlers in the state.
- January 15 – Algernon Sidney, British philosopher (d. 1683)
- February 2 – David Questiers, Dutch poet (d. 1663)
- March 4 – Jacob van der Does, Dutch landscape painter (d. 1673)
- March 24 – Ralph Hare, English politician (d. 1672)
- April 7 – Thomas Mainwaring, English politician (d. 1689)
- April 11 – Decio Azzolino, Italian Catholic Cardinal (d. 1689)
- April 20 – Olimpia Aldobrandini, Aldobrandini family member (d. 1681)
- April 23 – Sir John Chichester, 1st Baronet, of Raleigh, English landowner and politician (d. 1667)
- April 27 – Gryzelda Konstancja Zamoyska, Polish noble (d. 1672)
- April 30 – François de Laval, first bishop of New France (d. 1708)
- May 26 – William Petty (d. 1687)
- May 27 – Sir William Petty, English scientist and philosopher (d. 1687)
- May 29 – David Schirmer (poet), German lyric poet and librarian (d. 1686)
- May 30 – John Egerton, 2nd Earl of Bridgewater, English politician (d. 1686)
- May 30 – Wallerant Vaillant, painter of the Dutch Golden Age (d. 1677)
- June 8 – Paluzzo Paluzzi Altieri degli Albertoni, Italian Catholic Cardinal (d. 1698)
- June 15 – Cornelis de Witt, Dutch politician (d. 1672)
- June 19 – Blaise Pascal, French mathematician, physicist, and philosopher (d. 1662)
- June 29 – Inaba Masanori, Daimyo (d. 1696)
- July 1 – William Owfield, English landowner and politician (d. 1664)
- July 6 – Jacopo Melani, Italian composer and violinist (d. 1676)
- July 28 – Allen Brodrick, English politician (d. 1680)
- August 4 – Frederick Casimir, Count of Hanau-Lichtenberg (d. 1685)
- August 5 – (baptism) Antonio Cesti, Italian composer (d. 1669)
- August 13 – Sir John Morden, 1st Baronet, English politician (d. 1709)
- August 14 – Sir John Fowell, 2nd Baronet, English politician (d. 1677)
- August 23 – Stanisław Lubieniecki, Polish Socinian theologist (d. 1675)
- August 25 – Filippo Lauri, Italian painter (d. 1694)
- August 26 – Johann Sigismund Elsholtz (d. 1688)
- September 8 – James Bellingham, English politician (d. 1650)
- September 10 – Carpoforo Tencalla, Swiss-Italian Baroque painter of canvases and frescoes (d. 1685)
- September 13 – Pieter Wouwerman, Dutch painter (d. 1682)
- September 21 – Sir John Bowyer, 1st Baronet, English soldier and politician (d. 1666)
- September 23 – Georg Balthasar Metzger, German physician and scientist (d. 1687)
- October 4 – Robert Thoroton, English antiquary (d. 1678)
- October 9 – Ferdinand Verbiest, Flemish Jesuit missionary in China (d. 1688)
- October 17 – Francis Turretin, Swiss-Italian Reformed scholastic theologian (d. 1687)
- October 28 – Johann Grueber, Austrian Jesuit missionary and astronomer in China (d. 1680)
- November 1 – Zhu Youlang, Prince of Gui, the Yongli Emperor, the 4th and last emperor of the Southern Ming Dynasty of China (d. 1662)
- November 17 – Philip Sherard (MP), English soldier (d. 1695)
- November 22 – Bussy Mansell, Welsh politician (d. 1699)
- November 28 – Giovanni Battista Caccioli, Italian painter (d. 1675)
- December 1 – Christian Louis I, Duke of Mecklenburg (d. 1692)
- December 8 – Ernest, Landgrave of Hesse-Rheinfels (d. 1693)
- December 13 – Marc-René de Voyer de Paulmy d'Argenson (1623–1700) (d. 1700)
- December 16 – Ercole, Marquis of Baux, member of the House of Grimaldi (d. 1651)
- December 28 – Elisabeth Augusta Lindenov, daughter of king Christian IV of Denmark (d. 1677)
- date unknown
- January 15 – Paolo Sarpi, theologian (b. 1552)
- February 8 – Thomas Cecil, 1st Earl of Exeter, English politician (b. 1546)
- February – Malcolm Macfie, last chief of the Scottish clan Clan Macfie
- March 7 – Luís Mendes de Vasconcellos, 55th Grandmaster of the Knights Hospitaller (b. c.1542)
- March 25 – Henri de La Tour d'Auvergne, vicomte de Turenne, duc de Bouillon (b. 1555)
- April 19 – Uesugi Kagekatsu, Japanese samurai and warlord (b. 1556)
- June 16 – Christian, Duke of Brunswick-Lüneburg-Wolfenbüttel, German Protestant military leader (b. 1599)
- July 4 – William Byrd, English composer (b. 1543)
- July 8 – Pope Gregory XV (b. 1554)
- August 6 – Anne Hathaway, Shakespeare's wife
- October 21 – William Wade, English statesman and diplomat (b. 1546)
- November 9 – William Camden, English historian (b. 1551)
- November 11 – Philippe de Mornay, French writer (b. 1549)
- November 12 – Josaphat Kuncevyc, Lithuanian archbishop (b. c. 1582)
- date unknown – Andrea Andreani, Italian engraver (b. 1540)
- "Historical Events for Year 1623". OnThisDay.com. 2015. Retrieved 11 August 2015.
- Ferrand, Jacques. Maladie d'amour ou Mélancolie érotique.