1663 1664 1665 - 1666 - 1667 1668 1669
1630s 1640s 1650s - 1660s - 1670s 1680s 1690s
Events of 1666
- January 17 – Chair of St. Peter set above the Altar at Cathedra Petri, Vatican City.
- June 11–June 14 – Second Anglo-Dutch War – Four Days Battle: The Dutch fleet defeats England.
- The city of Piteå in Sweden is completely burned by a large fire
- July 25 – Second Anglo-Dutch War: English fleet defeats the Dutch under Michiel de Ruyter at St. James's Day Battle.
- August 5 – St. James's Day Battle: An English fleet defeats the Dutch under Michiel de Ruyter.
- August 9 – Rear Admiral Robert Holmes leads a raid on the Dutch island of Terschelling, destroying 150 merchant ships in the Vlie estuary, and pillaging the town of West-Terschelling, an act later referred to as Holmes's Bonfire.
- September 2 – Great Fire of London: A large fire breaks out in London in the house of Charles II's baker on Pudding Lane near London Bridge. The fire burns for 3 days, destroying 10,000 buildings including St. Paul's Cathedral, but only 16 people are known to have died.
- September 5 – The Great Fire of London ends.
- September 6 – Cestui que Vie Act 1666 passed in Parliament
- September 16 – Apostasy of Sabbatai Zevi
- December 22 – The Académie des sciences (French Academy of Sciences) is founded by Louis XIV.
- Expulsion of the Portuguese from the Bengal port city of Chittagong by Mughal forces of Emperor Aurangzeb under General Bujurg Umed Khan and renaming the city as Islamabad.
- Sir Isaac Newton uses a prism to split sunlight into its component colors, which helps us understand the nature of light more comprehensively (see optical spectrum).
- Dutch artist Johannes Vermeer paints The Art of Painting, his largest and most complex work.
- Lund University is founded in Lund, Sweden.
- Moulay al-Rashid conquers Fes, marking the beginning of Morocco's still-reigning Alaouite Dynasty.
- Jean Talon completes a census of New France, the first census in North America.
- The Russian Orthodox Church holds a sobor (church council) which deposes Patriarch Nikon, but accepts his liturgical reforms. Dissenters from his reforms, known as Old Believers, continue to this day.
- The year is also known for having all the Roman numerals, used only once, in order from biggest to smallest value (MDCLXVI = 1666).