If you answer that question, most likely you are giving an answer based on a calendar that goes all the way back to one put in place by Julius Caesar. Caesar’s calendar, aka the Julian Calendar, was pretty good, but it developed problems over time, so it was modified in 1582 by Pope Gregory XIII. This calendar, the Gregorian Calendar, what we’ve been using for the last several hundred years, and it works pretty well. Learn more about your ad choices. Visit megaphone.fm/adchoices