What accounts for the discrepancy? When Washington was born, Britain and its colonies were using the Julian calendar. Developed in first century B.C. under Julius Caesar, it had three too many leap days per 400-year period. The Catholic Church corrected the error in the 16th century by introducing a modified calendar (the Gregorian calendar) and skipping 10 days.
The Gregorian calendar was soon adopted by Catholic nations, but non-Catholic nations, such as Britain, were slower to change. The British calendar was also unique in the fact that it began its year on March 25 rather than January 1.
Britain amended its calendar in 1751 and 1752. First, it decreed that 1752 begin on Jan. 1 rather than March 25, meaning that the year 1751 lasted only nine months and 1752 lasted 15 months. It then adjusted to the Gregorian calendar by dropping 11 days in September 1752 (Sept. 3-13).
Historians usually adjust dates in the Julian calendar to correspond to the modern calendar, thereby creating a discrepancy in Washington’s birth date and other historical dates. In the most famous example, Russia’s Bolshevik Revolution of November 1919 is known as the October Revolution because Russia was still using the Julian calendar.
Find the best biographical and primary sources for George Washington in his findingDulcinea profile.
Learn about Abraham Lincoln, whose birthday is also celebrated in February.