• 1640 - Beginning of the Reaper's War in Catalonia between the Generalitat de Catalunya and the Spanish Crown after the uprising known as Corpus of Blood amidst the unrest caused by the presence of Castilian troops in Catalan territory during the Thirty Years' War.
• The personal union of the crowns of Spain and Portugal ends due to a revolution in the latter (1640). Philip IV of Spain is succeeded in the throne of Portugal by King John IV, previously Duke of Braganza
• 1641 - A Treaty of Offensive and Defensive Alliance is signed by Portugal and the Dutch Republic on July 12. The treaty has no effect in the Portuguese colonies under Dutch rule since it wasn't respected by both parties.
• Anthony van Diemen, colonial governor of the Dutch East India Company, assigns Abel Tasman with the mission to explore the Terra Australis (Oceania). During his two years' expedition (1642 - 1644), the latter becomes the first European to reach Van Diemen's Land (Tasmania) and New Zealand.
• Evangelista Torricelli constructs the first Mercury barometer (1643/ 1644).
• In England, the growing conflict between King Charles I of England, Scotland and Ireland and the Long Parliament results in the outbreak of the English civil war (1642 - 1649). Supporters are respectively called Royalists and Roundheads. The Parliament eventually emerges victorious. The captive King is put on trial (January 19 - January 27, 1649) and then executed by decapitation (January 30, 1649). The monarchy is abolished and briefly replaced by the Commonwealth of England (1649 -1653).
• During the English civil war, in 1644, John Milton's Areopagitica, William Walwyn's The Compassionate Samaritane, Henry Robinson's Liberty of Conscience and Roger William's The Bloudy Tenent of Persecution are published, marking the turning point in the Christian debate on persecution and toleration.
• China, in 1644: The invading Manchu army, with the help of Ming general Wu Sangui, captures Beijing. This marks the beginning of the Qing Dynasty (also known as the Manchu Dynasty), the last imperial dynasty of China.
• A series of treaties, known collectively as the Peace of Westphalia (October 24, 1648) put an end to:
  
  • The Eighty Years' War (1568 - 1648) between Spain and the Dutch Republic. The latter is recognized as being fully independent.
  • The Thirty Years' War (1618 - 1648) between the various Catholic and Protestant forces of Europe. Each of the about 360 German Princes of the Holy Roman Empire gains almost complete sovereignty over his/her respective territory/territories. Switzerland is recognized as being independent from the Empire.

World leaders