1582

1582 (MDLXXXII) was a common year starting on Monday in the Julian calendar.

This year, the Gregorian calendar was introduced by Papal bull.  The new calendar was adopted by Spain, Portugal, the Polish–Lithuanian Commonwealth and most of present-day Italy from the start.  In those countries, the year continued as normal until Thursday, October 4.  The next day became Friday, October 15.  France followed two months later.  Sunday, December 9 was followed by Monday, December 20.  Other countries continued using the Julian calendar, switching calendars in later years.  The conversion to the Gregorian calendar was completed in 1923.

 Events 
February 24 – The Gregorian calendar is made official.