Correction of the calendar. Historical artwork depicting the calendar reform in 1752, when England switched from the Julian Calendar to the Gregorian Calendar. Seen here are a baby and an old man, possibly representing the new and old ways of tracking the passage of time. The old man is crossing out dates from a calendar, which are the 11 days that were 'omitted' from the calendar between the 2nd September and the 14th September 1752. The changes corrected the drift in the calendar, which arose because the mean Julian calendar year was slightly too long. The Gregorian calendar system brought the calendar back into synchronization with the seasons and, to keep it there, adopted the leap year rule.