Adoption of the Gregorian Calendar in Great Britain (1752)

On September 2, 1752, the Kingdom of Great Britain made a significant change to its calendar system by adopting the Gregorian calendar. This reform was marked by an unusual occurrence where the day after September 2 was declared to be September 14. This adjustment was part of the wider ‘Calendar (New Style) Act 1750’, which dictated the transition from the Julian to the Gregorian calendar—a change aimed at correcting a drift in the calendar year that had accumulated over centuries.

Background

The Julian calendar, in use since the times of Julius Caesar, had introduced a system where a leap year occurred every four years. However, this calculation overshot the solar year by about 11 minutes annually. As a result, by the 16th century, the calendar year was approximately ten days behind the equinoxes and solstices it once aligned with.

To address this, Pope Gregory XIII introduced the Gregorian calendar in 1582, which refined leap year rules (eliminating leap years in century years not divisible by 400) to better align with the Earth’s orbit. While Catholic countries quickly adopted this reform, Protestant and Orthodox countries took longer. Thus, by the mid-18th century, the divergence between the two systems had increased to 11 days due to the cumulative error of the Julian system.

Transition in Great Britain

The decision to adopt the Gregorian calendar in Britain and its territories was formalized by the British Parliament with the Calendar (New Style) Act 1750. This legislation outlined that the then-current Julian calendar would give way to the Gregorian calendar in 1752. To implement the change, 11 days had to be omitted, prompting widespread public interest and confusion.

The transition’s most palpable effect was that the day following September 2, 1752, became September 14, 1752. Additionally, the start of the legal new year shifted from March 25 to January 1.

Impact and Aftermath

Though the calendar adjustment was straightforward, it stirred various reactions. Some historical accounts, albeit likely exaggerated or apocryphal, suggest there were public protests demanding the “return of the 11 days” because of perceived loss in daily life and financial disputes about leases and rents.

The change also had significant implications for historical record-keeping, with pre-transition documents sometimes carrying dual dates (known as “Old Style” and “New Style”) to clarify the calendar reference.

Ultimately, Britain’s shift to the Gregorian calendar facilitated synchronization with other European nations, enhancing navigation, trade, and international relations. The adjustment also set a precedent for future calendar reforms and alignment efforts worldwide.