When Virginians woke up on September 14, 1752, they must have felt like they had been asleep for eleven days. Well—not exactly.

Up to that point, England and its American colonies were still on the Julian calendar, first implemented by Julius Caesar in 46 B.C. In 1582 Pope Gregory XIII introduced the Gregorian calendar to correct deficiencies in the Julian calendar that affected the timing of seasonal equinoxes and Easter. Unlike Spain, Portugal and other Catholic countries, Protestant England held on to the old calendar.

In 1751, citing “divers[e] inconveniences,” “frequent mistakes” and “disputes” arising from the two calendars, Parliament passed the Calendar Act. This act authorized adoption of the Gregorian calendar and moved the beginning of the new year to January 1 instead of March 25, which England had recognized (legally) as the first day of the year since the 12th century. Dates between January 1 and March 24 often were written like this: January 9, 1722/23.

By this point, the Julian calendar was 11 days off from the Gregorian calendar and the true solar year. To remedy this, the Calendar Act declared that September 2, 1752 would be followed by September 14.

So Virginians and people in the American colonies and England indeed went to bed on September 2 and woke up on September 14. Ben Franklin for one found virtue in the switch, reporting that “It is pleasant for an old man to be able to go to bed on September 2, and not have to get up until September 14.”