If I read the linked article correctly, they’d adopted the Gregorian calendar for everything except the number of the year by 1917. The only change in 1926 was to make the year number coincide with the Western CE (though then still AD).
But the tax year also ran from Mar 25 to Mar 24, so the tax year number always corresponded exactly with the calendar year number.
The whole system made good sense in medieval society and even much later.
There were four ‘quarter days’ that corresponded roughly to the equinoxes and solstices:
- Lady Day (Mar 25)
- Midsummer Day (Jun 24)
- Michaelmas (Sep 29)
- Christmas (Dec 25)
In earlier times most rentals, contracts, and financial agreements ran between quarter days, rather than between months as ours do.
The majority of the population were farm workers, and all land tenancies ran for a year from Lady Day to Lady Day. This corresponded with the farming year, because you wanted farmers to be able to plough, sow, and harvest the same land without interruption. Mostly they would pay taxes and rents with produce rather than money.
Lady Day (~ spring equinox) was the start of the farming year, when the land was generally free from snow, the weather was moderating, and ploughing and other farm work could start in earnest. It was the logical time to start land tenancies.
It’s a bit difficult to disentangle the two. It’s true that the Rumi calendar made, in 1917, the same realignment with the tropical year that the Gregorian calendar had made in 1582, by means of omitting days. The years were, also after this realignment, still counted as from the Hijra, and it wasn’t until 1926 that the count started with the (supposed) birth of Jesus. However, as has been noted above, for the years after 1900, the leap year rules of the Julian and the Gregorian calendar coincide (and will do so until 2100), so it’s not really meaningfully possible to say whether the Rumi calendar was based on the Julian or the Gregorian one between 1917 and its final abolition in 1926.
It was all set out in the appendices to the Lord of the Rings. The Shire calendar started the new year on March 25, as was good and proper.
That actually gets me back to the OP. It’s true that the last year in which the number of days differed between the Gregorian calendar and the Julian calendar was 1900. The next year in which this will happen again will be 2100 (and thereafter, 2200, 2300, 2500, 2600 etc. - it will apply to every year evenly divisible by 100, unless the year is also evenly divisible by 400). Since many Orthodox churches still reckon the date of Christmas on the basis of the Julian calendar, that means that in those years the difference between “Western” and Orthodox Christmas will increase by one.
Somewhere I read that the Gregorian calendar is supposed to omit the leap year in every year divisible by 4000. None of us will ever see if that is actually implemented.
I don’t see where it says anything like that (English version), and anyway I hope that any calendar reform or standardization will not be controlled by the Church next time.
That’s been proposed several times (by John Herschel for example https://blog.klockit.com/2014/12/05/from-julian-to-gregorian-the-progress-of-timekeeping/ but isn’t official
Why shouldn’t it be? I can see that there are many things worth criticising about the Catholic Church, but as far as the Gregorian calendar is concerned, they did a fine job there - it is quite a well-designed calendar. Probably there was no institution around that could have done it at that time, both in terms of scientific know-how (actually, the Holy See has had a long-standing interest in astronomy for centuries, and still maintains an observatory) and in terms of the political influence to push for widespread (though not yet universal, at the time) adoption.
That would be workable - under the current leap day rule, the Gregorian calendar has an average duration of the year that is 0.0003 days too long. That adds up to one day in 3,333 years, so that after 4,000 years it would be worthwhile thinking about omitting a day. Doing so would reduce the irregularity of the calendar to one day in 20,000 years (which you could, of course, take care of by futher fine-tuning of the leap-day rule). But this exception has not (yet?) been instituted.
Actually it did occur to me that the future Catholic Church may well be the last concentration and redoubt of the kind of disinterested scientific expertise necessary to research and carry out such a reform. Who knows?
Quoting from Wikipedia:
If society in the future still attaches importance to the synchronization between the civil calendar and the seasons, another reform of the calendar will eventually be necessary. According to Blackburn and Holford-Strevens (who used Newcomb’s value for the tropical year) if the tropical year remained at its 1900 value of 365.24219878125 days the Gregorian calendar would be 3 days, 17 min, 33 s behind the Sun after 10,000 years. Aggravating this error, the length of the tropical year (measured in Terrestrial Time) is decreasing at a rate of approximately 0.53 s per century. Also, the mean solar day is getting longer at a rate of about 1.5 ms per century. These effects will cause the calendar to be nearly a day behind in 3200. The number of solar days in a “tropical millennium” is decreasing by about 0.06 per millennium (neglecting the oscillatory changes in the real length of the tropical year).[2] This means there should be fewer and fewer leap days as time goes on. A possible reform would be to omit the leap day in 3200, keep 3600 and 4000 as leap years, and thereafter make all centennial years common except 4500, 5000, 5500, 6000, etc. But the quantity ΔT is not sufficiently predictable to form more precise proposals (Blackburn & Holford-Strevens 2003, p. 692).
Note that the proposal is not simply to omit a day every 4000 years, nor does anyone think the future is sufficiently predictable at the current time.
Given the changes to the mean length of a day and a year over the time periods we’re discussing fixing the calendar over, it makes little sense to today decide how to handle leap years many millennia into the future. I suspect it will basically be an issue that will be dealt with similar to how the pre-Julian Roman Calendar worked: some group of leaders would decide on when a day will need to be added to prevent the drift of the equinoxes (or equinoctes for the pedantic) through the seasons. One hopes there would be sufficient unity in the secular world then that it wouldn’t be a problem.
[quote=“Schnitte, post:29, topic:926966, full:true”]
Why shouldn’t it be? I can see that there are many things worth criticising about the Catholic Church, but as far as the Gregorian calendar is concerned, they did a fine job there - it is quite a well-designed calendar. Probably there was no institution around that could have done it at that time, both in terms of scientific know-how (actually, the Holy See has had a long-standing interest in astronomy for centuries, and still maintains an observatory) and in terms of the political influence to push for widespread (though not yet universal, at the time) adoption.
[/quote]Not entirely.
One area they missed was the division into months. They could have fixed that, too.
Having 13 months, of 28 days each (every month being 4 weeks of 7 days) would be 364 days, leaving one New Year’s Day (2 in leap years). That would make things much more regular, with each date (like the 17th) always being the same day of the week in each month of the year. That would have been a useful improvement to the calendar.
Excellent idea . The only question is should the 1st be on a Sunday or a Monday
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There is already a kind of precedent with the insertion of “leap seconds”, those adjustments that keep 6 a.m. from slowly drifting towards the middle of the night. The International Earth Rotation Service just announces them a few months in advance, and so far it has been accepted, as far as I can tell, though on the other hand it has only been a few decades and there are still arguments; who knows what could happen over centuries, let alone millennia.
I can tell you now, business people, with their quarterly reports being so important, would be dead-set against it.
Yeah, certainly I had that in mind. The issue is that right now there is no real difference felt in anyone’s lives. Everyone matches their clock against something more official, and has no problem with the adjustment of a few minutes if necessary. A whole day would lead to people bickering about what day it was if, for instance, this country were still as polarized about absolutely everything.
It would also completely upset the liturgical calendar, so can see why it would be a no go for the Catholic church
It’s not like the Church has sole authority over the calendar. They came up with the change, but it’s individual nations which have adopted it.
In my industry this exact system is often used for scheduling. There are 13 “sked-months” of 4 weeks each. Plus 1 or two “leap-days” to keep things aligned with the ordinary calendar from year to year.
As to quarterly reports, and hoping I'm not being whooshed ...
In the 12-month system the quarters aren’t quarters: they’re 3-month intervals of differing length that do align with the funky irregular month boundaries, but not the regular weekly cycles.
In the 13 “month” system, “quarters” actually are exactly 1/4 of a year and are exactly 13 weeks and are exactly equal in length. And so they always contain the same number and alignment of weekdays and weekends. Which is a further advantage for those industries where that matters. They don’t align neatly with the months or “months”, but that’s irrelevant.