|Posted by Gilbert Stack on October 4, 2018 at 5:00 AM|
On this day (October 4) in 1582 Pope Gregory XIII introduced the Gregorian calendar to correct a .0075 day error in the Julian calendar introduced by Julius Caesar. As the calendar (relative to the equinoxes) had drifted 10 days since Caesar’s time, Gregory’s calendar jumped from October 4 to October 15 in 1852. From this point forward, the potential drift was corrected for with a new leap year rule. In years cleanly divisible by 100, there would be no leap year, unless the year was also cleanly divisible by 400, such as the year 2000.