On Tuesday, Jan. 17, the city of Philadelphia celebrated Benjamin Franklin's 300th birthday. According to the Boston Globe, Franklin was actually born on Jan. 6, 1706, but that was before the colonies switched from the Julian to the Gregorian calendar. When Great Britain updated to the new system by skipping 11 days in 1752, Franklin dutifully moved his birthday. Did everyone change birthdays in 1752?

No. Most people were happy to keep their original dates. The Gregorian calendar had been in effect for most of Europe since the 16th century, when Pope Gregory XIII issued a papal bull that established the new system. Not everyone went for the idea right away, and Great Britain held out for 170 years. (The Church of England was particularly resistant to the proposal from Rome.) Some people protested when Parliament finally made the change. Posters were drawn up saying ,"Give us back our eleven days."

Franklin supported the change from the start. "Be not astonished," he wrote in his Almanack, "nor look with scorn, dear reader, at such a deduction of days, nor regret as for the loss of so much time …" Other prominent Americans supported the new system; George Washington updated his own birthday from the old Feb. 11 to the Gregorian Feb. 22. Even so, the majority of early Americans held on to the birthdays they'd always used....