Gregorian and Julian calendars

My understanding is that the only difference between the Gregorian and Julian calendars is that the Julian calendar has a leap year every 4 years, while the Gregorian has a leap year every 4 years except years that are divisible by 100 (except years divisible by 400).

Is that correct?

And so would it be correct to say that the last year in which the Gregorian and Julian calendars had a different number of days was 1900?

Yes those are the differences and 1900 was the last different year (Well except for Sweden/Finland) but then they weren’t on either calendar exactly.

I think this is technically correct, but AFAIK the Julian calendar was no longer in use anywhere by 1900.

On a related note, does this discrepancy account for Christmas being on 12/25 rather than 12/21? My understanding is that Christmas was originally a festival that took place on the winter solstice. These days that’s usually on 12/21. Would the solstice be most likely to fall on 12/25 if we were still on the Julian calendar? Would it have mostly fallen on that date back when the early Christians made 12/25 Christmas?

I’m asking this for a trivia contest I write, so “technically correct” is the best kind. I don’t allude to it being used anywhere anymore, and it does still EXIST, so I think it’s all good.

Thanks to both for the responses.

It was still in use in Russia in 1900. The Soviets adopted the Julian calendar in 1918.

Don’t know if any other eastern European countries were still using it then.

Plus, it is still used for liturgical purposes by Orthodox churches, which have not accepted the new-fangled popish calendar.

No. The Julian calendar instituted in 45 BCE aligned the vernal equinox with the 25th day of March, or VIII kalends Aprilis. So the winter solstice would have been on about 25 December in the Julian 12-month calendar.

But by the time that the birth of Jesus was accepted as 25 December in the western Roman Empire, in the fourth century CE, the vernal equinox had slipped back to about 21 March (XII kalends Aprilis) and the winter solstice to around 21 December. That was why the first Nicene Council in 325 put the vernal equinox at the date 21 March, and that’s the date Pope Gregory was trying to realign the equinox with in the Gregorian calendar reform.

If we had stayed on the Julian calendar right along, the winter solstice would now be in the first week of December, not on December 25.

Yes. Hence the great trivia question - “In what month did the October Revolution occur?”

(the answer is “November” (by the Gregorian calendar))

The Julian Calender was still used in many of the countries of the Russian Empire like Estonia and Latvia. Outside of that the Gregorian Calendar was adopted by China in 1912 (though they weren’t using the Julian one at the time), by Bulgaria in 1916, Turkey (Ottoman Empire) in 1917, and perhaps most surprisingly not until 1923 by Greece.

It’s not surprising that Eastern Orthodox countries were slow to adopt a Catholic update of the calendar.

For the same reason, it look Protestant Britain (and America) until 1752 to adopt the Gregorian calendar, 170 years after the Catholic countries.

The change to the Gregorian calendar in the Protestant countries of Europe was driven by growing trade, banking, and communication with Catholic countries. Having different dates in different countries was a confusing hassle, and nobody could deny that the change was reasonable and necessary.

In eastern Europe there wasn’t so much trade with western countries, so there wasn’t the same incentive to adopt the change until the 20th century.

I believe Sweden had cleared up its unique experiment with calendar reform by 1900. They had adopted the Gregorian calendar for secular use in 1753 and for religious use informally in 1825 and formally in 1844.

Favorite piece of calendar trivia: Miguel de Cervantes and William Shakespeare both died on April 23, 1616 but Cervantes died ten days before Shakespeare.

Another piece of calendar trivia: although we celebrate George Washington’s birthday on February 22nd, he was born on February 11, 1732. The British Empire adopted the Gregorian calendar in 1758 by moving all dates forward by 11 days: September 1, 1758 was followed by September 13, 1758.

I think you’ll find that the date I gave above is correct. The British parts of America changed to the Gregorian calendar in 1752, not 1758.

Wed 2 Sep, 1752 was followed by Thu, 14 Sep 1752.

 

Washington was born on February 11, 1731 (Old Style).

Before 1752 the new year started on Mar 25, not Jan 1, in Britain and its colonies, so February was still considered part of the previous year.

i.e. in Old Style dating Mar 24, 1731 was followed by Mar 25, 1732.

Thank you. I stand corrected. It was 1752, not 1758.

And I didn’t know that about the Old Style calendar starting on March 25. Interesting.

Not all of Britain: From the BBC website, “March 25 was celebrated as the traditional date of the Scottish New Year until 1599. In that year, Scotland converted to the modern Gregorian Calendar. England did not adopt the new calendar until the Calendar Act of 1751 was passed, a full 152 years after Scotland.”

That’s not correct.

From the wiki article I linked to above:

In Scotland, the legal start of the year had already been moved to 1 January (in 1600), but Scotland otherwise continued to use the Julian calendar until 1752.

I wasn’t really sure about the Gregorian calendar reference myself. It was the date of New Year’s Day in Scotland I was concerned with. I believe it had the effect that “20th February 1720” would mean 2 different dates a year apart, on either side of the Scotland - England border (leaving aside 3rd or 4th dates that it might signify in other countries). Sometimes significant historic anniversaries have been celebrated in the wrong year as the organisers haven’t checked whether the historical record was dated in the English system or the Scottish one.

Turkey used the Rumi calendar (“Rumi” meaning Roman), a derivative of the Julian calendar, until 1926, when the Gregorian one was introduced as part of the Westernisation of the country under Atatürk.

[ninja’ed]

I know this is accurate, and I’ve known it for decades. But it still hurts my brain, as in, it’s a great example of “I can’t wrap my brain around it.”

I don’t have much problem with the fact that calendar years, school years, fiscal years, and others, overlap in different ways. But this is on a whole nother level.

Y2K was a headache, but it was a one-off event. Incrementing the year number on March 25, year after year, must have driven the bookkeepers crazy.