Birthdays of people born under Julian Calendar, but living after adoption of Gregorian Calendar

[Paul Theroff]

I've often wondered about the consequences of changing from the Julian to the Gregorian calendar. Does a person born in 1731, old style, use the old-style date as birthday, or the new one?

Here is one example showing that the new-style date was recognized as the birthday. Lady Emily Lennox is said to have been born 6 October 1731 (old style), but in 1767 her sister speaks of the birthday being on 17 October (which would be the new-style date).


Lady Holland to Duchess of Leinster, 8 October 1767:

"Next Friday seven'ight, dear sister, we propose to go to Dover, and hope to embark the next day, which will be the I7th, your birthday.."

[David Beamish]

King George III was born on 24 May 1738, but after 1752 celebrated his birthday on 4 June, a date still celebrated at Eton College. That makes sense as otherwise anyone's next birthday after September 1752 would have been eleven days early.