1582    Pope Gregory XIII announces the Gregorian calendar.

1582    Pope Gregory XIII implements the Gregorian Calendar. In Italy, Poland, Portugal, and Spain, October 4 of this year is followed directly by October 15.

1582    Because of the implementation of the Gregorian calendar this day does not exist in this year in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar, this day is skipped in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar, this day is skipped in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar this day does not exist in this year in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar, this day does not exist in this year in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar, this day does not exist in this year in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar this day does not exist in this year in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar, this day does not exist in this year in Italy, Poland, Portugal and Spain.

1582    Because of the implementation of the Gregorian calendar this day does not exist in this year in Italy, Poland, Portugal and Spain.

1582    Pope Gregory XIII implements the Gregorian calendar. In Italy, Poland, Portugal, and Spain, October 4 of this year is followed directly by October 15.

1690    Battle of the Boyne (Gregorian calendar) – The armies of William III defeat those of the former James II.

1700    Sweden introduces its own Swedish calendar, in an attempt to gradually merge into the Gregorian calendar, reverts to the Julian calendar on this date in 1712, and introduces the Gregorian Calendar on this date in 1753.

1700    Sweden introduces its own Swedish calendar, in an attempt to gradually merge into the Gregorian calendar, reverts to the Julian calendar on this date in 1712, and introduces the Gregorian Calendar on this date in 1753.

1752    Great Britain adopts the Gregorian calendar, nearly two centuries later than most of Western Europe.

1752    The British Empire adopts the Gregorian calendar, skipping eleven days (the previous day was September 2).

1753    In Sweden February 17 is followed by March 1 as the country moves from the Julian calendar to the Gregorian calendar.

1873    Japan begins using the Gregorian calendar.

1912    The Republic of China adopts the Gregorian calendar.

1918    The Gregorian calendar introduced in Russia by decree of the Council of People's Commissars effective from February 14(NS)

1918    Russia adopts the Gregorian Calendar.

1918    The Soviet Union adopts the Gregorian calendar (on 1 February according to the Julian calendar).

1925    Turkey adopts the Gregorian Calendar.

1927    Turkey adopts the Gregorian calendar: December 18, 1926 (Julian), is immediately followed by January 1, 1927 (Gregorian).