The British (and by extension, the colonists) waited until 1752 to make the jump from the calendar created by Julius Caesar in 45 BC to the one commissioned by Pope Gregory XII in the 1580s, our current standard. They landed about 11 days off the mark.
The solution: At one second after midnight on September 2, 1752, it became September 14.
Of course, all birthdates followed suit—including George Washington’s. Born on February 11, 1732 (according to the Julian calendar), George celebrated his 20th on February 22, which is the date we use today.
If you’re looking to celebrate that special day with us, you can do so a few days before George’s actual birthday. Washington Crossing Historic Park will celebrate Washington’s 286th birthday at the Visitor Center on Sunday, February 18, from 10 AM to 2 PM. Admission is only $1.