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Note from the Archives: Boston's two birthdays

Is Boston's birthday on September 7 or 17? The answer is more complicated than you realize!

Before 1582, almost all of Europe used the Julian calendar, a calendar put into place by Julius Caesar in 45 BCE. The Julian Calendar used a 365 day solar year, just like we do now, but it counted leap years differently. By the Middle Ages, people started to notice that equinoxes were 10 days too early in the Julian calendar. The European church began to worry that they were not celebrating religious holidays on the right dates.

In 1582, Catholic Pope Gregory approved the Gregorian or "new style" calendar. This calendar corrected some of the flaws in the Julian calendar. In the Gregorian calendar, leap years happened less often. The new calendar also moved New Year's Day from March 25 to January 1.  

Most of Europe followed the Pope's directions to switch calendars. However, England's Queen Elizabeth I, a protestant, had no intentions of using the Catholic pope's calendar. For almost 200 years, England used a different calendar than her European neighbors!  When English and European settlers began to colonize North America, they brought their warring calendars with them. European colonies typically used the Gregorian calendar and English colonies used the Julian calendar. When we look at the earliest records in the City Archives, we see records dated using the Julian calendar.

Boston Town Book, 1633
Boston Town Book, 1633

However, as time passed, many English colonists began to celebrate New Year's Day on January 1. Colonists would also sometimes date documents using both the Julian and the Gregorian date to avoid confusion. For example, these records from Brewster, Massachusetts show dates that were in 1731 in the Julian calendar and in 1732 in the Gregorian calendar. The record keepers dated them 1731/2.

Brewster records in The Mayflower Descendant: A Quarterly Magazine of Pilgrim Genealogy and History, Volume 6
Records of Town of Brewster, 1731/2

Finally, in 1750, England's Parliament decided to adopt the European calendar. By this point, the English calendar was 11 days out of sync with the rest of Europe. The Calendar Act ordered that starting in in 1752:

  • the formula for calculating leap years would change
  • New Year's Day would change from March 25 to January 1, and
  • 11 days would be dropped from September 1752 to bring the English calendar in sync with the European calendar.

In September 1752, Bostonians skipped September 3-13. Bostonians went to bed on Wednesday, September 2  and woke up on Thursday, September 14! To help avoid confusion, popular almanacs like "Old Richard's" as well as newspapers like the Boston Gazette explained the calendar change. Bostonians seem to have adjusted to the new calendar easily. Our records from 1752 barely mention the missing 11 days! 

Although Bostonians at the time took the calendar change in stride, the shift in dating has often confused people reading older documents.  Dates before 1752, when the Julian calendar was used, are referred to as "old style" dates. Dates after 1752 are referred to "new style" dates. If we use the old Julian "old style" dates, Boston's birthday is on September 7. If we use the current Gregorian calendar or"new style" dates, Boston's birthday is September 17.

In 1866, Boston Mayor Frederic Lincoln gave an address about Boston's history, and noted our city's two birthdays.

Fredric Lincoln Address 1866

Over time, Boston shifted to celebrating its birthday on the new style date of September 17. In 1930, Boston's 300th anniversary, the City planned a week of festivities centered around an illuminated parade and pageant on September 17.

Tercentenary schedule and budget, 1930
Tercentenary schedule and budget, 1930, Committee on the Tercentenary


City officials designated September 17 "Boston Day", and planned "the largest parade in Boston history." You can see plans for the parade below

Boston Tercentenary Parade plans and route, 1930
Boston Tercentenary Parade plans and route, 1930

Thousands of Bostonians turned out for the parade as you can see below!

Boston Tercentenary Parade, 1930
Boston Tercentenary Parade, 1930

Boston Tercentenary Parade, 1930
Boston Tercentenary Parade, 1930

Although Boston has recently embraced September 17 as its birthday, some Bostonians prefer to use the old style date of September 7. We suggest that you celebrate both days!

Want to read more about the history of  Old Style and New Style dating? Take a look this blog post from our friends at the Massachusetts Trial Court Law Library, or this post from our friends at the Connecticut State Library!

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