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Comment by comeonbro | Hacker News Reader

I didn't appreciate until recently that the calendar we live by today was personally designed by Julius Caesar.

Like not by some forgotten technocrats incidentally during his time, but Julius Caesar himself as a subject matter expert, as a side-project. With consultation, certainly, but by his initiative, from long-standing engagement with the problem in one of his early jobs from long before he was a main character of the Roman story.

Digestable and entertaining (fragment of a) video on the topic:

https://www.youtube.com/watch?v=fD-R35DSSZY&t=1312s

View on HN

People mostly remember Caesar as a ruler, however in 63 BC (5 years before the Gallic wars) Caeser managed to get himself elected as Pontifex Maximus (chief high priest).

Adjusting the calendar was as part of the duties of the Pontifex Maximus. They decided public holidays and they decided whether to add an "intercalary month" (at the end of February which used to be the last month).

There are many interesting things to say about this but since this is hacker news I'm going ro focus on one:

Caesar was away campaigning a lot and the Pontifex could adjust the calendar only while physically in Rome. So many years went by without calendar fixes.

After having benefited from the confusion and the edge he had by understanding the calendar (like knowing he could safely cross the Adriatic when his opponent assumed that crossing it that given month was a bad luck) he decided to fix the calendar so that it doesn't require a human in the loop.

In a way, he automated himself out of his job.

Completely off-topic, but someone on HN posted a theory that Caesar let himself be killed, because he was afraid that he wasn't able to keep up his stellar reputation as winning everything as he got older. Was one of the few "eye-openers" for me, since as you get older, nothing is really "new" or "interesting". If the parent post turns out to be true, it goes on that list. Will research after work.

At least a dozen engineers read this and decided to name their new microservice "Pontifex"

Imagine being so powerful that your enemies await your calendar adjustments

And in that calender, February is the last month, which makes it the logical month for adjusting leap years.

And likewise, September is the 7th month, October the 8th, etc etc

It looks like there's a legend that this was the case, but January has been the first month of the year through all of recorded history, and Julius Caesar's version was no different.

EDIT: Because there's a lot of confusion in several replies I thought I'd clarify: February was the second month in Julius Caesar's calendar. Romans in the Republic describe the month as being at some point the last month in the calendar, but we don't have any direct record of that. That's what I mean when I refer to it as a legend: it's a story that later Romans tell about their distant past. It is probably accurate but the sources are too far removed from the actual event to be treated as primary sources.

This is true of Roman history in general: any story that dates back to the kings should be treated as a legend that Romans told about their past. It may have elements of the truth, but shouldn't be taken as firm fact. This particular legend has a lot of evidence going for it, but that doesn't make it inaccurate to refer to it as a legend.

https://en.m.wikipedia.org/wiki/Februarius

That article seems to state the opposite?

> In the oldest Roman calendar, which the Romans believed to have been instituted by their legendary founder Romulus, March was the first month, and the calendar year had only ten months in all. Ianuarius and Februarius were supposed to have been added by Numa Pompilius, the second king of Rome, originally at the end of the year. It is unclear when the Romans reset the course of the year so that January and February came first.

Most of what we know about pre-republican Rome is from oral tradition, not actual records. So if by the time of the Republic February was the second month of the year, it was the second month of the year through all of recorded Roman history.

Maybe Quintilis, Sextilis, September, October, November and December were the seventh, eight, ninth, tenth, eleventh and twelfth months of the year through all of the “recorded Roman history”. But it seems well accepted that they were once the fifth, sixth, seventh, eight, ninth and tenth months of the year.

In retrospect, I probably shouldn't have referred to it as a legend. That seems to have negative connotations for most people that I didn't mean to convey.

I really don't doubt the authenticity of the story, I mainly was trying to indicate that we don't know when the change occurred but it certainly happened a long time before Caesar: by his day, the change was an oral tradition whose full story was lost in the very distant past.

>That seems to have negative connotations for most people that I didn't mean to convey.

Not just "for most". It has negative connotations (of the kind reffered to here) for all people.

"Legend" connotes "didn't take place".

I'm a person, and legend does not have that connotation for me, it means "it was only handed down orally so we can't be sure". I'm sure my idiolect is unusual in that regard, but I stand by my "for most people".

A legend is a traditional story sometimes regarded as historical but isn't authenticated. You are saying that a legend is a story that is believed to be false. That is exactly opposite from the meaning of the word and is NOT something believed by "all people."

That article says "it is unclear when the Romans reset the course of the year so that January and February came first", but doesn't actually deny that the year formerly ended with February.

See for example p.187 of https://ryanfb.github.io/loebolus-data/L333.pdf for a 1st century BC reference to it:

> The Terminalia 'Festival of Terminus,' because this day is set as the last day of the year; for the twelfth month was February, and when the extra month is inserted the last five days are taken off the twelfth month.

To be clear, I'm not denying that it was the first month at some point. It wasn't when Caesar designed his calendar, and we don't have a record of it changing. I refer to it as a legend not to indicate that it isn't true but to indicate that the only sources we have are referring to it as changing sometime in the distant past.

It is very likely that at its origin the Roman year started on the spring equinox.

That is why March was the first month and February was the last Month.

However, the astronomical rule was not followed later, and due to the inconsistent length of the year the position of the spring equinox had drifted from the 1st of March to around the 25th of March by the time of Julius Caesar.

The present position of the spring equinox around the 20th of March does not correspond to its position at the introduction of the Julian calendar, but to its position around the time of the First Council of Nicaea (AD 325).

No it hasn't. Your link even points out that Jan and Feb were added to a 10 month calendar starting with March. Moreover, various cultures notionally observing the Julian calendar have assigned varying dates to the start of the year throughout history.

It says that later Romans said that they started with the 10-month calendar and that the second king added 2 months, and that at some point those two months migrated to the front.

The context that I did not include in my original comment and should have is that everything from Rome in the time of the kings is considered to be legend. There are likely things that are rooted in fact, and this story has strong evidence for it, but the number and order of months has not changed in recorded Roman history, we only have indications from later Romans that they believed it changed at some point in the past.

My main point was that Caesar did not have February as the last month, he used the same order as his contemporaries and as we do.

As a Persian, I always found the Gregorian calendar weird. In Iran and some other countries, Jalali calendar is used which is much more straightforward:

https://en.wikipedia.org/wiki/Jalali_calendar

   The Iranian calendar (also known as Persian calendar or the Jalaali Calendar) 
   is a solar calendar currently used in Iran and Afghanistan. It is 
   observation-based, rather than rule-based, beginning each year on the vernal 
   equinox as precisely determined by astronomical observations from Tehran.

There are 12 months. The first 6 have 31 days and the rest have 30 days, except the last month which is 29 days. Every 4 years, it's a leap year and the last month becomes also 30 days.

It's also precisely set to follow seasons. For example, the first day of Fall is actually the first day of "Mehr" (the 7th month). For some reason, the Gregorian calendar has it on Sep. 22.

For what it's worth many early European cultures also considered the start of the year to be at the start of spring, generally the same idea as Nowruz, which is where we got Easter from as a conglomeration of "pagan" rituals and Christian religion. Unfortunately we ended up with this weird Dec. 31st at the end of a year in the middle of winter which doesn't make any logical sense.

There’s more similarities than just that. Iran was founded by Indo-Europeans.

Many similarities in languages too. Persian (Farsi) has the same root as some European languages (and should not be confused with Arabic, which is totally different than both).

    In Persian | In English
    mädar      | mother
    barädar    | brother
    dokhtar    | daughter
    pedar      | father
    bad        | bad
    ...

I’m familiar. It is fascinating. Same with Sanskrit. I don’t know if we’re all descended from the same people exactly, or if the Indo Europeans were just an extremely successful core group with a culture that all of us adopted as the natives wherever they spread to. But they certainly had a successful culture. Iran should really be an ally with the western democracies. Those people are actually pretty advanced and modern, considering where they are placed in the world.

I say that to my American and European friends, that Iranians have a lot more in common with them than with the rest of the middle east. There are exceptions, of course, but the general public is really well educated, open minded, and leaning towards Western values and culture.

Too bad that the country has received such a negative reputation over the past 4 decades due to its (non-Iranian) regime.

I’m American and that’s my perspective. I can’t be the only one. I never even understood why Iran and the US were at odds. Seems entirely based on politics/elites. From what I see, Iranians would be my first pick as allies in the region. We certainly chose poorly with Saudi Arabia.

Non-Western values and culture are a great portion of why we need Iran. A shelter from and an antidote to global liberal hegemony.

> It's also precisely set to follow seasons. For example, the first day of Fall is actually the first day of "Mehr" (the 7th month). For some reason, the Gregorian calendar has it on Sep. 22.

This doesn't really work; the first day of Fall differs from place to place according to the specifics of the local climate.

https://en.wikipedia.org/wiki/Equinox

Why would that be considered the first day of Fall? Even taking a purely astronomical perspective, the autumnal equinox would be the center of Fall, not the beginning.

As a not-at-all neutral observation, you post an enormous amount, are obnoxious in your confidence, and frequently wrong.

This seems a bit mean, especially given its a pretty natural question as to why the equinox is considered start of fall instead of midautumn (in certain regions)

Edit: i take it back.

Because https://en.wikipedia.org/wiki/Seasonal_lag

Yes, from a seasonal perspective, the timing of a season varies idiosyncratically from place to place. That was the first thing I said. Why would you then want to locate the beginning of Fall on the equinox?

Quoting from your link:

> seasonal lag is not "seasonally symmetric"; that is, the period between the winter solstice and thermal midwinter (coldest time) is not the same as between the summer solstice and thermal midsummer (hottest time).

> In mid-latitude continental climates, [seasonal lag] is approximately 20–25 days in winter and 25–35 days in summer.

> there is no meteorological reason for designating these dates as the first days of their respective seasons.

You asked why it is traditionally known as that, and i answered.

Not only did I not ask that, I don't believe that the equinox is traditionally known as the beginning of autumn. Traditional terminology always marks the solstices and equinoxes as the middle of the season in which they occur, because that is obviously the way seasons work. Compare Western European "Midsummer" [the solstice] or Chinese 立秋 ["beginning of Fall", August 8; compare to the equinox on September 23, or to the "Mid-Autumn Festival" 中秋节, fixed to the full moon, but generally around late September].

The equinoxes and the solstices are marked on modern calendars as the beginning of their respective seasons, but I have never heard anyone attempt to justify that. I tend to assume it's the result of the calendar-buying population not having any reason to care what season it currently is.

But even among modern calendar-buying people, I believe they think of big snowdrifts as something that happens in winter, not something that happens in late fall and continues through winter. And the calendar doesn't agree with that.

So is it astronomical season or weather season? Weather varies between locations.

Spring and autumn start on the equinox, summer and winter on the solstices. Though it's true they tend to be called "mid summer" and "mid winter" day. It's certainly weird.

We also tend to associate summer with days getting longer and winter with days (the period between sunrise and sunset) getting shorter, but the opposite is true: in summer, which is the period from about 21 June to 23 September, days are getting shorter, whereas in winter, between 21 December and 21 March, days are getting longer. Astronomical winter starts on the shortest day, and astronomical summer on the longest day.

I guess we're just eternally confused about calendars. And who can blame us?

> Astronomical winter starts on the shortest day, and astronomical summer on the longest day.

This is a convention used only by modern calendars. Astronomers have no opinion on when particular seasons occur. They care about things like when stars rise above or sink below the horizon. But they don't use the change in the sky to determine when winter occurs. People notice that winter occurs around the same time every year, and they associate whatever the sky is doing at that time with the beginning of winter.

As you already note, the solstices are called "midsummer" and "midwinter". That is because they are traditionally identified as the middle of summer and the middle of winter. Why do you believe that they are the beginning instead?

"Believe"? It's the common definition. Belief has nothing to do with it.

That doesn't come close to being true. Compare the Cambridge dictionary's "common definition":

> [summer] the season of the year between spring and autumn when the weather is warmest, lasting from June to September north of the equator and from December to March south of the equator

Wikipedia:

> Summer is the hottest of the four temperate seasons, occurring after spring and before autumn. At or centred on the summer solstice, the earliest sunrise and latest sunset occurs, daylight hours are longest and dark hours are shortest, with day length decreasing as the season progresses after the solstice. The date of the beginning of summer varies according to climate, tradition, and culture.

> From an astronomical view, the equinoxes and solstices would be the middle of the respective seasons, but sometimes astronomical summer is defined as starting at the solstice, the time of maximal insolation, often identified with the 21st day of June or December. By solar reckoning, summer instead starts on May Day and the summer solstice is Midsummer.

It "doesn't come close to being true", so you post stuff that confirms what I said?

Only your last sentence presents an alternate definition, the rest confirms it or is close to it. And the astronomical definition is not an uncommon one.

I think you need to reread what I wrote and what you wrote.

Technically days get longer (hours of daylight) during the winter and shorter during the summer.

Bruh.

You can't really define seasons with day-precision based on weather or climate.

You can't define seasons with day precision based on anything.

1/4 of the time it takes for earth to cross a line between the sun and a particular feature of the CMB, granted the CMB feature would be arbitrary

That would not match anyone's idea of what a season was. For example, it makes it impossible to say "as you go farther north, the winter gets longer and the summer gets shorter".

That actually works pretty well and has worked well for thousands of years for what it was designed to do. The calendar should not necessarily follow the local climate of every region, as that can vary each year and throughout the time. They had to fix a reference point for seasons, and they have chosen the Equinox. This is a sensible reference point (see refs). But also it could be anything else as long as it's measurable and verifiable independently and does not change based on location.

The same works for the clocks. People in Sweden still use the same 24-hour clock, even though they have vastly different daylight conditions in different seasons.

The Persian calendar is actually our most precise [1] calendars to date, and it owes its precision to tying the calendar to astronomical seasons [2].

[1] https://www.timeanddate.com/date/perfect-calendar.html [2] https://www.timeanddate.com/calendar/persian-calendar.html

Calendar seasons are mainly used to talk about the weather. Using Equinox as a fixed reference point is not any more precise than using meteorological convention wrt thermal seasons.

Here is what Equinox means and how it's related to weather in general https://www.weather.gov/lmk/seasons

> Using Equinox as a fixed reference point and a is not any more precise than using meteorological convention wrt thermal seasons

Well, no. What meteorological convention? That's a pretty broad term. We are talking about calendars, not a general weather forecast system, as I was comparing Persian calendar with other calendars.

With Equinox, you get a good indication of weather conditions for a wide geography while having a precise reference point to design a calendar which can be used for other equally important purposes.

P.S. While I was thinking about what you wrote, I wondered how these things were argued and arranged in ancient times and what did they think or say considering what they had to come up with affects a significant portion of the civilized world and trade between nations.

Yes. My partner is Iranian and their birthday is out of sync (earlier) every leap year. We “discovered” that the one first year it happen to us when suddenly received birthday wishes by all their Iranian network the day “before” the Gregorian calendar birthday.

> For example, the first day of Fall is actually the first day of "Mehr" (the 7th month). For some reason, the Gregorian calendar has it on Sep. 22.

That’s just a convention. In Russia we use “meteorological” convention, for example, and so each season starts on the 1st of some month (March, June, September, December). It is off from the astronomical convention by ≈20 days and it is off from reality by whatever depending on your location and your feelings on what constitutes seasons.

The Julian calendar, which the Gregorian is a revision of, was designed precisely so that societies didn't need a public servant dedicated to keeping the calendar up to date.

>For example, the first day of Fall is actually the first day of "Mehr" (the 7th month). For some reason, the Gregorian calendar has it on Sep. 22.

The particular locations of the equinoxes and solstices on the calendar isn't as important as keeping them more or less in the same places as time goes on.

> but January has been the first month of the year through all of recorded history

Are you kidding? Not only are September through December literally named "Month 7" through "Month 10", but the year began in late March as recently as AD 1751. That is not a period where we're suffering from a lack of recorded history.

September through December being months 7 to 10 are because Julius Caesar (July) and Augustus Caesar (August) added months named after themselves after they were named.

No, that never happened. They renamed the existing months "5" and "6".

Huh, TIL

True enough, my mistake! I was only looking at the Roman time period and didn't realize that the calendar shifted back to starting in March during the Christian era. That's really interesting to learn!

My main point is still the same: Caesar's calendar started in January and he was following the order that was current in his day. We do not know when the switch from March to January occurred. There are multiple stories about the switch (the supposed dates range from 750 BC to 153 BC), and there are legends of a 10-month calendar that didn't include January and February at all, but there are no extant contemporary records describing the switch.

The legends about the 10 month calendar are almost certainly a very late invention, which appeared as an attempt to explain why e.g. December is the 12th month.

It is likely that at its conception all the months of the Roman calendar were numbered, but some time later the months January to June were given names corresponding to important religious festivals, which were scheduled during those months.

> but there are no extant contemporary records describing the switch.

We have something of a philosophical disagreement; I would argue that the names of the months themselves constitute a contemporary record describing the switch. It doesn't tell us when the switch occurred, but it tells us very clearly that the switch occurred.

It is true that the record might be accidentally or deliberately falsified; perhaps the months were originally named after unrelated concepts and the names got revised into their numerical forms over time. But a formal history suffers from exactly the same problem, and it still gets to be called a "record"; I don't see why we would consider the fact that our ninth month is named "Month Seven" not to be a record of a shift in the beginning of the year [or rather, in the beginning of the sequence of months].

> the calendar we live by today was personally designed by Julius Caesar

Pope Gregory has entered the chat

there have been some changes to the calendar since Caesar, especially when people went to bed Thursday 4 October 1582 and woke up on Friday 15 October 1582, and thereafter there were no more leap years on centuries except every 400 years.

https://www.onthisday.com/articles/gregory-conquers-julius-c...

One fun historical tidbit is that St Teresa of Ávila died on the night of the 4th to the 15th of October, 1582.

https://en.wikipedia.org/wiki/Teresa_of_%C3%81vila#Last_days

He didn't just throw dice or march in, see what's what and grab the locals by the nadgers.

JC was quite a chap and of course why its called the Julian Calendar. Many other calendars are available. Kalends is the source of the name for calendar and the Roman day of month counting is pretty involved - http://www.polysyllabic.com/?q=calhistory/earlier/roman/kale... Kalends, nones and ides.

JS died on the ides of March ...

JS died how?

Et tu Brute? He was murdered in the Senate.

The cut and thrust of political discussion was rather more forthright back then.

To be fair, we've chopped off the heads of King Charles hereabouts. I'm sure III has nothing to worry about.

Typo, it's JC

Ah, the one the epoch is based on?

I thought that was Linus Torvalds.

React

I’m unsure how commonly known this is, but also note that July and August are named after Julius Caesar and Emperor Augustus

If Caesar designed the calendar, how did he get a month in there named after something that hadn’t happened yet? When Caesar died Augustus’ name was Octavian, and Rome hadn’t had an emperor yet…

Are you messing around?

Octavius became Julius Caesar after he was adopted. And also later he was given the honorable designation by the senate and called Augustus. That’s not his name its one of his honors.

Octavian is essentially a past tense of his name and he never truly went by that. It’s a name used by historians.

> Octavius became Julius Caesar after he was adopted.

Gaius Julius Caesar

At the time of the calendar reform, the months that are now called July and August were called Quintilis and Sextilis. The Julian calendar came into use on January 1, 45 BC. July was renamed in 44 BC (the year of Caesar’s assassination), and August in 8 BC.

Designing the calendar does mean "give a name to every month forever".

You could also (a) just design the mechanics of the calendars (leap days, duration of months, etc), but keep the month names the same, or (b) change names too, which could get renamed again later.

Well worth the watch, also shows that Ceasar's main character arc was bossted by his calendar knowledge and authority.

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