1670 was a common year beginning on a Saturday in countries using the Julian calendar and a Wednesday in countries using the Gregorian calendar.

Events

• January 21 – Highwayman Claude Duval is executed in Tyburn, Middlesex
• April - Pope Clement X is elected.
• May 2 - The Hudson's Bay Company is formed in England.
• May 26 - In Dover, Charles II of England and Louis XIV of France secretly sign a treaty ending hostilities between their kingdoms
• Phosphorus is discovered by Hennig Brand.
• Blaise Pascal's Pensées is posthumously published.
• England gains formal possession of Jamaica
• Les Invalides constructed by Louis XIV of France
• First French settlers in modern-day Senegal
• Rebellion of Cossacks in Ukraine crushed
• Henry Morgan captures Panama

Births

• January 24 - William Congreve, English playwright.
• May 12 - King Frederick Augustus I of Poland (+ 1733).
• August 21 - James FitzJames, 1st Duke of Berwick, illegitimate son of the Duke of York (the later James II of England) and later French military commander.
• December 7 - John Aislabie, Director of the South Sea Company.

Deaths

• February 19 - King Frederick III of Denmark
• March 10 - Johann Glauber, German-Dutch alchemist and chemist
• May 23 - Ferdinando II de' Medici, Grand Duke of Tuscany (b. 1610)
• June 30 - Henrietta Anne Stuart, Princess of Scotland, England and Ireland, Duchess of Orléans.