1610 (MDCX in Roman numerals) is a 17th century year.
7 January: Galileo Galilei observes the Galilean moons of Jupiter for the first time, discovering Callisto together with Simon Marius.
January 11: Galileo Galilei and Simon Marius discover Ganymede.
March 12: Swedish troops under Jacob De la Gardie conquer Moscow.
March 12: first copy of Sidereus Nuncius, an astronomical treatise by Galileo Galilei, printed on that day, together with other 449 subsequent copies, in a modest printing house by Tommaso Baglioni in Venice.
April 25: signature of the Treaty of Bruzolo, a secret alliance between Henry IV of France and Carlo Emanuele I of Savoy signed in the Castle of Bruzolo.
May 14: Henry IV of France is assassinated by François Ravaillac, a religious fanatic, a few days after his wife Maria de 'Medici was crowned queen.
6 June: Francis de Sales and Giovanna de Chantal found the Order of the Visitation of Saint Mary in Annecy.
June 10: The first Dutch settlers settle on the island of Manhattan.
July 18: after four years of life in continuous flight, the great painter Caravaggio dies on the beach of Porto Ercole, probably of malaria.
October 17: After Henry IV of France is assassinated by a fanatic friar Louis XIII of France, he is crowned king.
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