100 Mind-Blowing Commission Facts

But Sosigenes made a bit of a miscalculation, so the calendar continued to be a little off. He thought a year lasted 365.25 days. It’s around 365 days, five hours, 48 minutes, and 45 seconds, equivalent to about 365.242 days. This tiny error had some pretty big consequences: By 1577, the Julian calendar was off by 10 days, meaning key Christian holidays were being celebrated on incorrect dates. Pope Gregory XIII took issue with this and established a commission to get the calendar back on track. In 1582, the Gregorian calendar was created. Rather than having an extra day every four years without exception, years that are divisible by 100—like 1700 or 1900—skip leap year. Unless the year is also divisible by 400, like the year 2000, in which case the Leap Year is back on! Even this system isn’t perfect, though: It has an error of one day in 3236 years.