"Calendar glitch hai," the third user commented on Instagram. "By 1582, the Julian calendar, with a Leap Day every four years, had accumulated TEN extra days relative to Earth's orbit.

In 1582, Pope Gregory XIII introduced the Gregorian calendar. Prior to this, most of the Roman world and Europe had used the Julian calendar, introduced by Julius Caesar in 45 BCE.

No action was taken, however, with the Julian calendar continuing to be used until 1562-63. The Council of Trent passed a decree calling for the pope to fix the calendar – but it took another ...

The calendar had 10 days missing, which shocked everyone. While everything appears to be in order in the calendar, the only catch is that the date October 4 is preceded by October 15 in the year 1582.

Adoption of the calendar, which replaced the older lunar and Julian calendars, was a drawn-out affair. While most Catholic countries switched over within the year, the non-Catholic world was ...

"By 1582, the Julian calendar, with a Leap Day every four years, had accumulated TEN extra days relative to Earth's orbit. So Pope Gregory jump-started his new and exquisitely accurate calendar by ...

Russia, however, remained on the Julian calendar until after the 1917 Russian Revolution (which is thus called the “October Revolution” though it occurred in Gregorian November), and Greece ...