How Calendars Work How Do Savants Do It?
Because it made sense in early agricultural societies for the calendar to have personal meaning, the months are approximately linked to the moon’s revolution around the earth and the year is related to the earth’s revolution around the sun. Since the link is only approximate, there must be little corrections and consequently some months have 30 days and others have 31 days, except for February which has 28 days except for leap year, when it has 29 days. Despite these corrections, the Julian calendar used in medieval times had accumulated enough error that Pope Gregory declared that ten days would be eliminated in October of 1582. That correction still serves us today, which means that should you learn how to calculate calendar dates, you’d be fine as long as you never tried anything before 1583. To reduce the need for corrections in the future, Pope Gregory’s astronomers introduced a minor complication into the rule that every fourth year was a leap year; namely that any year divisible
