| Year | Month | Day | Event |
|---|---|---|---|
| 1582 | Feb | 24 | Pope Gregory XIII Started The Gregorian Calendar |
| 1618 | Sep | 18 | Mesoamerican Count Begins With Twelfth Baktun |
| 1806 | Jan | 01 | Abolishment Of French Republican Calendar |
| 1885 | Jan | 01 | Twenty-five Nations Adopt Sandford's Standard Time |
| 1923 | Feb | 15 | Greece Last European Adopter Of Gregorian Calendar |
| 1930 | Jun | 16 | Sovnarkom Establishes Decree Time In The USSR |
| 1972 | Jun | 30 | First Leap Second Added To UTC |