There are eleven days in September 1752 that did not happen. In Britain and its colonies — which at the time included most of what became the eastern United States — Wednesday 2 September was followed by Thursday 14 September.
Not skipped, not renamed. Simply never dated. And the hole is still sitting in the calendar program on your computer, which is how most people find out about it.
Try it yourself
On a Mac or any Linux machine, open a terminal and type:
cal 9 1752 | Prints September 1752 — with the second followed by the fourteenth |
Unix calendar utilities reproduce the historical British calendar rather than a clean arithmetic one, so the gap has been quietly preserved in computing for decades. Generations of programmers have hit it by accident and assumed they had found a bug.
Why eleven days had to go
The Julian calendar assumed a year of exactly 365.25 days. The actual solar year is roughly eleven minutes shorter.
Eleven minutes a year sounds like nothing. It accumulates at about one day every 128 years, and the Julian calendar had been running since 45 BC. By the 1750s the calendar was eleven days ahead of the seasons — the equinox was arriving on the wrong date, and the drift was still growing.
The Gregorian reform fixed the ongoing error by changing the leap-year rule, and fixed the accumulated error by deleting the surplus days in one go. There is no gentle way to remove eleven days.
Why Britain was 170 years late. Catholic Europe adopted the Gregorian calendar in 1582, on the authority of a papal bull. Protestant Britain was not inclined to accept a calendar issued by the Pope, and so spent nearly two centuries keeping different dates from its neighbours across the Channel — which meant that for that whole period, a letter sent from London to Paris arrived before it was written, as far as the dates on the paper were concerned. Merchants and diplomats handled it by writing both dates. The reform finally passed as an act of Parliament, and the delay had far more to do with religious politics than with astronomy, which nobody seriously disputed.
The other half of the change, which causes more confusion
The same reform moved the start of the legal year in England from 25 March to 1 January.
Before this, a date such as 10 February 1750 fell after 10 December 1750, because the year did not turn over until late March. This is why historical documents sometimes carry double-dated years like 1750/51, and why dates from before 1752 need care rather than assumption.
It also means anyone comparing pre-1752 English dates to European ones is dealing with two separate mismatches at once: a different day count and a different year boundary.
“Give us our eleven days”
The best-known part of the story is the mob that supposedly rioted, believing the government had stolen eleven days of their lives.
It is a wonderful story and the evidence for it is thin. The phrase comes from a Hogarth painting of an election scene, where it appears on a banner — in a work about electoral chaos rather than calendar reform. Historians have long questioned whether calendar riots occurred at all in the form popularly described.
There were real grievances, and they were duller and more reasonable than a mob: people were concerned about rent, wages and interest falling due on dates that had just vanished, and about whether they would be charged a full quarter for a short one. Those questions were addressed in the legislation. “Parliament passed provisions adjusting payment dates” simply makes a worse painting.
Why the story survives anyway
Because it is the kind of history that feels true. A government deleting days is exactly the sort of thing people expect governments to do badly, and a crowd shouting for its days back is a more satisfying image than a clause about quarterly rents.
The genuinely strange fact needs no embellishment: for eleven days in September 1752, in Britain and in America, the date did not exist. And it still does not, every time somebody types cal 9 1752.
Britain and its territories, including the American colonies, adopted the Gregorian calendar in 1752 under legislation passed by Parliament, with Wednesday 2 September 1752 followed directly by Thursday 14 September 1752, removing the dates 3 to 13 September. The same reform moved the start of the legal year in England from 25 March to 1 January. Catholic states in Europe had adopted the Gregorian calendar from 1582. The correction was required because the Julian year exceeded the solar year by approximately eleven minutes, accumulating an error of roughly one day per 128 years. Unix and Linux cal utilities reproduce the historical British calendar and display the gap for September 1752. The popular account of riots demanding the return of the eleven days is disputed by historians, and the phrase “give us our eleven days” originates from a painting by William Hogarth depicting an election scene. Readers interested in the detail should consult the text of the legislation and scholarly histories of the reform.
Frequently Asked Questions (FAQ)
What happened in September 1752?
Britain and its territories, including the American colonies, changed from the Julian calendar to the Gregorian calendar. To correct the accumulated drift, eleven dates were removed: Wednesday 2 September 1752 was followed directly by Thursday 14 September 1752.
Which days are missing?
3 to 13 September 1752 inclusive. Those dates never occurred in Britain or its colonies.
Why does my computer show the gap?
Unix and Linux calendar programs reproduce the historical British calendar. Running the command cal 9 1752 prints September with the eleven days absent, which is why so many people encounter this by accident.
Why was the change needed?
The Julian year was about eleven minutes longer than the solar year. That small error accumulated at roughly one day every 128 years, and by 1752 the calendar had drifted eleven days out of step with the seasons.
Did people riot demanding their eleven days back?
Probably not in the way the story suggests. The phrase “give us our eleven days” comes from a Hogarth election painting, and historians have long questioned whether any such riots took place. It is one of the most repeated pieces of history that has little evidence behind it.
Did anything else change?
Yes. The same reform moved the start of the legal year in England from 25 March to 1 January, which is why dates in earlier documents can appear to belong to the wrong year.
