"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.

Cultures throughout history have come up with their own unique ways to track the days, months, and seasons.

The Julian Calendar assumed that the sun’s circuit is exactly 365.25 days (thus providing a leap year every four years). In actuality, the sun takes 365.2422 days to complete its path.

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.

In 1582, Pope Gregory XIII introduced the ... What it boiled down to was that Sweden resynchronized itself with the old Julian calendar by adding an extra leap day, Feb. 30, to 1712.

But over time, that slight misalignment compounded and meant the Julian calendar wasn't aligned perfectly with Earth's orbit.In 1582, the Catholic Church wanted to correct this mistake by ...

Cue the modern calendar. Pope Gregory XIII brought the seasons back into alignment in 1582 by eliminating the 10 extra days. That year, Thursday, October 4 was followed by Friday, October 15.

In 1582, France implemented the Gregorian calendar. The country previously used the Julian calendar until the Council of Trent called for a change in 1563 , according to the History Channel.

The birth of the Julian calendar. Finally, in 45 B.C., ... Only with Gregory’s 1582 reform did January 1 really stick as the beginning of the new year—for many.