# Introduction of Gregorian Calendar - 10 days omitted
**URL:** https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587
**Category:** Factual Questions
**Created:** [August 6, 2004, 9:43am UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587 "2004-08-06T09:43:56Z")
**Posts on this page:** 17
**Page:** 1
### Author:  [@Schnitte](https://boards.straightdope.com/u/Schnitte)
#### Post date: [August 6, 2004, 9:43am UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/1 "2004-08-06T09:43:56Z")
In 1582, the Julian Calendar was abolished (at least in Catholic countries) and replaced by the Gregorian one in order to correct the inaccuracy of the Julian system. As part of the transition, ten days in October were omitted from the count - October 4, 1582 was followed by October 15. So far, so good. My question is: Were the days of the week adjusted accordingly, or not? I mean, let’s assume October 4, 1582 was a Monday (I don’t know if it was). Was October 15 a Tuesday, or a Friday, as it would have been if the 10 days in between would have been counted normally?
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### Author:  [@Popup](https://boards.straightdope.com/u/Popup)
#### Post date: [August 6, 2004, 10:22am UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/2 "2004-08-06T10:22:36Z")
> [@Schnitte](#):
>
> My question is: Were the days of the week adjusted accordingly, or not?
No.
Otherwise there would have been a problem when different countries changed system. For example when Sweden changed in 1753 the calendar was 11 days out of whack, and if the days of the week had been adjusted accordingly we would be two weekdays out of rythm, while still on the same numerical date.
For more info than you want, read the [Calendar FAQ](http://www.tondering.dk/claus/cal/node3.html).
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### Author:  [@APB](https://boards.straightdope.com/u/APB)
#### Post date: [August 6, 2004, 10:24am UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/3 "2004-08-06T10:24:06Z")
4 October 1582 Old Style was a Thursday, while 15 October New Syle was a Friday.
Quite apart from the fact that there was no obvious reason why the week days should change, a major consideration was that, whereas the months and the years were very obviously conventions invented by man, the seven-day week was thought to have been ordained by God.
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### Author:  [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)
#### Post date: [August 6, 2004, 10:24am UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/4 "2004-08-06T10:24:45Z")
> [@](#):
>
> [Calendar Calculations](http://www.grc.nasa.gov/WWW/K-12/Numbers/Math/Mathematical_Thinking/calendar_calculations.htm)
>
> The Gregorian calendar came into use in Roman Catholic countries in October 1582 when the seasons were brought back into step by eliminating 10 days from the calendar then in use. Thursday, October 4, was followed by Friday, October 15 (which caused some consternation among the populace, especially those with birthdays on the eliminated dates!). Britain and its colonies did not introduce the Gregorian calendar until September 1752 by which time an additional one day correction was required (actually, {1752 - 1582} x 0.0078 = 1.33 day).
> [@](#):
>
> [Calendar & Easter History](http://users.chariot.net.au/~gmarts/calfacts.htm)
>
> The change from the Julian to the Gregorian calendar took place in England and her dominions in 1752, when the correction was made by the omission of eleven days; Wednesday, September 2nd being followed by Thursday, September 14th.
–
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### Author:  [@bonzer](https://boards.straightdope.com/u/bonzer)
#### Post date: [August 6, 2004, 10:37am UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/5 "2004-08-06T10:37:55Z")
David Ewing Duncan’s _The Calendar_ (Fourth Estate, 1998, p290) reproduces the page from Magini’s 1582 edition of his _Novae Ephemerides_ with the astronomical table for month of October. Both the Old and New Style dates are included alongside each other, with the latter showing the jump from the 4th to the 15th. The Sundays are marked with a “C” next to them and, as posters have been saying, remain the same day (though differently numbered) in both calendars.
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### Author:  [@Bytegeist](https://boards.straightdope.com/u/Bytegeist)
#### Post date: [August 6, 2004, 2:43pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/6 "2004-08-06T14:43:14Z")
Obscure geeky question coming up…
The Unix utility **cal** faithfully displays the break from the Julian to Gregorian calendars — _as happened in the English-speaking world_. If you invoke “cal 9 1752” on my machine you get:
```auto
September 1752
S M Tu W Th F S
1 2 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
```
So, that’s nifty. On the other hand, **cal** for October 1582 displays a perfectly normal October, because that’s just what it was. For “us”, anyway.
Now then, in the Catholic countries of Europe and Latin America, does **cal** place the divide in 1752 or 1582?
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### Author:  [@Mycroft\_H](https://boards.straightdope.com/u/Mycroft_H)
#### Post date: [August 6, 2004, 2:57pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/7 "2004-08-06T14:57:19Z")
“Nineteen days hath September,
April, June and …” Wait a moment!? :smack:
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### Author:  [@yabob](https://boards.straightdope.com/u/yabob)
#### Post date: [August 6, 2004, 3:25pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/8 "2004-08-06T15:25:50Z")
> [@Bytegeist](#):
>
> Obscure geeky question coming up…
>
> The Unix utility **cal** faithfully displays the break from the Julian to Gregorian calendars — _as happened in the English-speaking world_. If you invoke “cal 9 1752” on my machine you get:
>
> ```auto
>
> September 1752
> S M Tu W Th F S
> 1 2 14 15 16
> 17 18 19 20 21 22 23
> 24 25 26 27 28 29 30
>
> ```
>
> So, that’s nifty. On the other hand, **cal** for October 1582 displays a perfectly normal October, because that’s just what it was. For “us”, anyway.
>
> Now then, in the Catholic countries of Europe and Latin America, does **cal** place the divide in 1752 or 1582?
Note that the cal utility doesn’t reflect another adjustment - England chose to adopt the “start of the year = January” convention at the same time as the Gregorian calendar shift, hence the “old style” date convention which reflected both the (by then) 11 day adjustment, and a different year for dates prior to March 21 on the old calendar. The fact that England adopted both of these reforms at the same time is one reason they get conflated in many people’s minds.
Reconciling historical European calendar dates is a non-trivial matter. Different jurisdictions adopted reforms at different times.
I suspect that the cal utility as distributed by most UNIX vendors reflects a Gregorian switch at 1752, and a naive assumption concerning the start of the year in all locales.
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### Author:  [@Duckster](https://boards.straightdope.com/u/Duckster)
#### Post date: [August 6, 2004, 3:41pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/9 "2004-08-06T15:41:37Z")
Russia did not convert until 1918!
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### Author:  [@yabob](https://boards.straightdope.com/u/yabob)
#### Post date: [August 6, 2004, 3:54pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/10 "2004-08-06T15:54:57Z")
Dates of adoption of the Gregorian calendar:
[http://www.sizes.com/time/cal\_Gregadoption.htm](http://www.sizes.com/time/cal_Gregadoption.htm)
Note the entry on Sweden - they attempted to adopt it piecemeal, by dropping leap years until they synched up. It didn’t work out, and they wound up declaring a “February 30” one year to resynch with the Julian calendar, eventually jumping to the Gregorian calendar at a later date.
And this doesn’t even consider the “beginning of the year” nonsense, which was out of synch all over the place.
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### Author:  [@Rayne\_Man](https://boards.straightdope.com/u/Rayne_Man)
#### Post date: [August 6, 2004, 4:57pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/11 "2004-08-06T16:57:38Z")
> [@Duckster](#):
>
> Russia did not convert until 1918!
That is why the \*October Revolution \* is celebrated ( or at least it was in the time of the USSR ) in November
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### Author:  [@dtilque](https://boards.straightdope.com/u/dtilque)
#### Post date: [August 6, 2004, 6:55pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/12 "2004-08-06T18:55:51Z")
Dropping the 10 (or 11 or whatever) days resynched the calendar to what it would have been if the Gregorian had been in place since the 3rd century. Why that century and not the first (either AD when Jesus was alive or BC when Caesar established the calendar – these would be the same thing) is something I’ve never understood.
BTW, the Russians adopting the Gregorian gave rise to an interesting bit of trivia. By the 20th century, the adjustment was 13 days. The Russians decided to drop them at the beginning of February so that Jan 31 was followed by Feb 14. That made Feb 1918 in Russia only 15 days long, the shortest month ever.
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### Author:  [@yabob](https://boards.straightdope.com/u/yabob)
#### Post date: [August 6, 2004, 7:02pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/13 "2004-08-06T19:02:53Z")
> [@dtilque](#):
>
> Dropping the 10 (or 11 or whatever) days resynched the calendar to what it would have been if the Gregorian had been in place since the 3rd century. Why that century and not the first (either AD when Jesus was alive or BC when Caesar established the calendar – these would be the same thing) is something I’ve never understood.
>
> …
This comes up from time to time. They were correcting the calendar to coincide with officially recognized astronomical observations made in the early part of the 4th century.
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### Author:  [@Rayne\_Man](https://boards.straightdope.com/u/Rayne_Man)
#### Post date: [August 6, 2004, 7:10pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/14 "2004-08-06T19:10:12Z")
Both the Russian and Greek Orthodox Churches still use the " old " calender. This is why Christmas is celebrated by them on our January 6 and Easter is that much later than the other Western churches.
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### Author:  [@yabob](https://boards.straightdope.com/u/yabob)
#### Post date: [August 6, 2004, 7:10pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/15 "2004-08-06T19:10:26Z")
More specifically, to the date of the equinox (March 21) as observed at the time of the first council of Nicea in 325 AD, which established the date for Easter.
An account which mentions this:
[http://www.hermetic.ch/cal\_stud/cal\_art.html](http://www.hermetic.ch/cal_stud/cal_art.html)
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### Author:  [@rocking\_chair](https://boards.straightdope.com/u/rocking_chair)
#### Post date: [August 6, 2004, 10:59pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/16 "2004-08-06T22:59:06Z")
christmas eve is jan. 6th, christmas is jan. 7th.
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### Author:  [@Yllaria](https://boards.straightdope.com/u/Yllaria)
#### Post date: [August 6, 2004, 11:11pm UTC](https://boards.straightdope.com/t/introduction-of-gregorian-calendar-10-days-omitted/258587/17 "2004-08-06T23:11:52Z")
Then I was born on Christmas! (And so was Millard Fillmore.)