1618

Events 
 March 8 – Johannes Kepler discovers the third law of planetary motion (he soon rejects the idea after some initial calculations were made but on May 15 confirms the discovery).
 May 23 – The Second Defenestration of Prague – Protestant noblemen throw three representatives of Ferdinand II out of a window. The event began the Thirty Years' War.
 July 20 – Pluto reached, according to sophisticated mathematical calculations, its second most recent aphelion. The next one occurred in 1866, and the following one will occur in 2113.
 August 29 – Johan van Oldenbarnevelt and Hugo Grotius are imprisoned by Maurice of Nassau, Prince of Orange
 October 29 – English adventurer, writer, and courtier Sir Walter Raleigh is beheaded for allegedly conspiring against James I of England.

 The margraves of Brandenburg is granted Polish approval to inherit Ducal Prussia.
 November 13, the Synod of Dordrecht has its first meeting.
 Change of emperor of the Ottoman Empire from Mustafa I (1617-1623) to Osman II (1618-1622).
 The 3000 seat Teatro Farnese, the first permanent proscenium theatre, was built into the Great Hall of the Palazzo della Pilotta in Parma, Italy in 1618.