This article is about the year 1654.
Year 1654 (MDCLIV) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar and a common year starting on Sunday of the 10-day slower Julian calendar.
- March 12–13 – The Treaty of Pereyaslav is concluded in the city of Pereyaslav during the meeting between the Cossacks of the Zaporozhian Host and Tsar Alexey I of Russia, following the end to the Khmelnytsky Uprising in Ukraine, which had started in 1648 and had resulted in the massacre of an estimated 100,000 Jews.
- April 5 – The Treaty of Westminster, ending the First Anglo-Dutch War, is signed.
- April 11 – Anglo-Swedish alliance: A commercial treaty between England and Sweden is signed.
- April 12 – Oliver Cromwell creates a union between England and Scotland, with Scottish representation in the Parliament of England.
- May 8 – Otto von Guericke demonstrates the power of atmospheric pressure and the effectiveness of his vacuum pump using the Magdeburg hemispheres before Ferdinand III, Holy Roman Emperor, and the Imperial Diet in Regensburg.
- June 3 – Louis XIV of France is crowned at Rheims.
- June 6 – Charles X Gustav succeeds his cousin Christina on the Swedish throne. After her abdication on the same day, Christina, now the former reigning queen of a Protestant nation, secretly converts to Catholicism.
- July – The Russian Army seizes Smolensk, and the Thirteen Years War starts between Russia and Poland over Ukraine.
- July 10 – Peter Vowell and John Gerard are executed in London for plotting to assassinate Oliver Cromwell.
- August – Oliver Cromwell launches the 'Western Design', an English expedition to the Caribbean to counter Spanish commercial interests, effectively beginning the Anglo-Spanish War (which will last until after the English Restoration in 1660). The fleet leaves Portsmouth in late December.
- August 22 – Twenty-three Jewish refugees from Brazil settle in New Amsterdam, forming the nucleus of what will be the second largest urban Jewish community in history, that of New York City.
- September 3 – In England, the First Protectorate Parliament assembles.
- September 12 – Oliver Cromwell orders the exclusion of the members of Parliament who are hostile to him.
- October 12 – The Delft Explosion, in the arsenal, devastates the city in the Netherlands, killing more than 100, among whom is Carel Fabritius (32), the most promising student of Rembrandt.
- October 31 – Ferdinand Maria, Elector of Bavaria, is crowned. His absolutist style of leadership becomes a benchmark for the rest of Germany.
- November 23 – French mathematician, scientist, and religious philosopher Blaise Pascal experiences an intense mystical vision that marks him for life.
- January 17 – Paulus Potter, Dutch painter (b. 1625)
- February 18 – Jean-Louis Guez de Balzac, French writer (b. 1594)
- March 24 – Samuel Scheidt, German composer (b. 1587)
- June 10 – Alessandro Algardi, Italian sculptor and architect (b. 1598)
- July 9 – Ferdinand IV of Germany (b. 1633)
- August 28 – Axel Oxenstierna, Lord High Chancellor of Sweden since 1612 (b. 1583)
- August 31 – Ole Worm, Danish physician and antiquary (b. 1588)
- September 7 – Yom-Tov Lipmann Heller, Bohemian rabbi and liturgical poet (b. 1579)
- October 12 – Carel Fabritius, Dutch artist (b. 1622)
- October 30 – Emperor Go-Komyo of Japan (b. 1633)
- November 30 – John Selden, English jurist (b. 1584)
- December 5 – Jean François Sarrazin, French writer
- date unknown – An Calbhach mac Aodha O Conchobhair Donn, the last inaugurated King of Connacht