| January 23 | France and Sweden sign anti-German Treaty of Barwald |
| February 5 | Rhode Island, founder, Roger Williams arrives in Boston from England |
| May 17 | Earl Johann Tilly attacks Maagdenburg |
| May 18 | English colony Massachusetts Bay grants puritarian voting right |
| May 18 | John Winthrop is elected 1st governor of Massachusetts |
| May 20 | German army under earl Johann Tilly conquerors Maagdenburg |
| May 30 | France/Maximilian van Bavarian signs Accord of Fontainebleau |
| June 19 | Peace of Cherasco: Charles de Gonzaga-Nevers becomes duke of Mantua |
| September 13 | Admiral Tholen conquerors 30+ Spanish frigates |
| September 17 | Battle of Breitenfeld: King Gustaaf Adolf defeats General Tilly |
| October 10 | Saxon army occupies Prague |
| November 4 | Ferdinand of Austria installed as land guardian of S Netherlands |
| November 7 | Pierre Gassendi observes transit of Mercury predicted by Kepler |
| December 6 | 1st predicted transit of Venus (Kepler) is observed |
| December 16 | Mount Vesuvious, Italy erupts, destroys 6 villages and kills 4,000 |
