What day of the week was the Ides of March, 44BC?

I know the Ides was 15th March, but I was idly wondering what day of the week Julius Caesar was killed. (I’m assuming this date is in the Julian Calendar, which was introduced in 45 BC.)

I did a cursory web search, but it’s complicated. There seems to be a lot of different things to take into account: the difference from our Gregorian calendar, changes in the lengths of months, what happened between 1BC and 1AD, leap years, what date the year in question started, whether days have always been continuous, and doubtless more.

Also as an aside and if anyone knows, what’s the oldest event for which we have the exact date i.e. day-month-year? What day of the week was it? (I’ve a theory that Tuesday is the most rubbish day of the week.)

It was a Wednesday. Trust me.


Definitely the funniest thing I’ve read today. :smiley:

Your question is ultimately sort of meaningless (although as you’ve discovered it can be calculated, in a complicated way) because the Romans of the time (even with the Julian calendar) did not have a 7-day week (which is a Late Imperial development) but rather an 8-day cycle (9 with Roman inclusive counting) called a nundinum (the 8th day being known as the nundinae), which was really only used for calculating market days and was not really the equivalent of our weekday. That is, for example, none of Cicero’s letters see fit to mention what letter (the nundinum cycle was lettered A-H, not numbered) a day was.

To sum up, it might have been a Wednesday working backwards from our way of calculating, but no one in Rome would have thought of it as a Wednesday.

BTW, the Ides of March are a ‘B’ day, as the cycle restarts itself every year with Jan. 1st as an ‘A’ day.

Many sources cite a battle between Lydia and Media on May 28, 585 B.C., as the oldest event in history to which a reliable date can be assigned, because of an eclipse which took place on the day of the battle. I assume that the date is rendered in the Julian, and not the Gregorian, calendar.

I have no idea what day of the week that would have been in either calendar, if anybody had been following either calendar or observing the modern 7-day week at the time.

Just as a side note, the Romans did not “develop” the 7-day week, they rather took it over around the time they adapted Christianity. The Christians, in turn, have it from the Jews, who considered the Roman “week” kind of heretic, which is one of the reasons why Genesis emphasizes the 7-day cycle so much.
However, I do not know whether the Jews developed this concept on their own or they adapted it from one of the numerous peoples they met. Does anybody know that?

Sorry for the slight hijack, but OTOH this might help answer the side question of the OP. Regarding the theory about Tuesdays, this may need to be changed to Mondays for times when the week started with Sunday, and Saturday (Sabbath) was the end of the week.


This hypothesis seems unlikely. The Torah was written in the mid-13th century BCE. See Who wrote the Bible? (Part 1). Rome was not founded until the mid-8th century BCE, and did not become an international power or exert significant influence in regions where Judaism was practiced until a few centuries later still.

Admitted, that’s true. I should not have said they considered the Roman habit heretic, but the habit of the peoples surrounding them, at least of those who did not have a 7-day week.
I have been too sloppy writing that post. Sorry.

OTOH, you also seem a bit sloppy to me in reading that the Torah was written in the mid-13th century BC from the cite you have given. The cite also says that this is not undisputed, and there are several facts that indicate otherwise.
In particular, there are two stories of creation: The one where God makes Adam from earth (rather crude, believed to be the older one), and the one where God creates everything in 6 days and rests on the seventh day (rather modern in style, believed to be considerably newer). I related to the modern story, which is the one that emphasizes the 7-day week, and while it surely was written before Rome was founded, it is likely quite a bit newer and not from the mid-13th century BC.

Sorry, I have to go to a meeting now. I will search for cites when I come back and post any findings.

I know that we have exact dates for many Babylonian events, also based on astronomical observations, and I’m pretty sure that those predate 585 BC. Checking my textbooks, I find reference to systematic records of Venus dating back to the reign of Ammisaduqa, 1646-1626 BC. Offhand, I don’t see references to any specific events in that time frame, but I suspect that things like the birth of an heir would be recorded.

Chronos, correct me if I’m wrong, but I was under the impression that the translation of those Babylonian astronomical event dates into modern terms is basically done on a “best fit” basis rather than based on continuous history, meaning that one couldn’t really call them “exact dates.” (In other words, there are no continuous ancient chronicles that would allow us to conclusively state, say, that a particular sighting of Venus occurred exactly 1602 years before the assassination of Julius Caesar; but given that we have at least an approximate idea of when Ammisaduqa reigned, we can fine-tune it based on these astronomical observations. But if our approximation of Ammisaduqa’s era is wrong, then those dates would need to be recalibrated.)

Whereas the 5/28/-585 date could be considered exact, given that Greek historical writings allow us to place that battle in (or very close to) that year independently of the astronomical evidence.

In principle, any single astronomical observation, if precise enough, could give you an exact date for the observation. In practice, yes, there is in fact some inprecision, so you need rough information on when the event took place (how rough the other information needs to be depends on how precise your astronomy is). But once you have that bracketing time frame, the astronomical records can give you pinpoint accuracy. It’s my understanding that the other historical evidence together with the astronomical records are good enough to pin down Babylonian dates with high confidence, but this isn’t my specialty, and it’s been some years since I studied it, so I may be mistaken on that.

But http://www.terra.es/personal2/grimmer/ and http://quasar.as.utexas.edu/BillInfo/doomsday.html show a simple way to calculate any day according to our standard calendar today.

Even then, it is not necessarily correct, because there are many periodic additions or subtractions necessary with our modern, standard calendar in order to keep the seasons in line. I think the last one was around the turn of the 19th/20th century…I believe an hour was subracted…http://scienceworld.wolfram.com/astronomy/LeapYear.html

According to this page, December 31st in 1 BC was a Friday (thereby giving everybody a weekend in which to recover from the Millennium celebrations). Shouldn’t be too laborious to work back to 44 BC from there. However, I’ve no idea whether that page takes into account the minor Augustan adjustments to the Julian Calendar in the first decade of the 1st Century AD.

It’s not my speciality either, but the oldest date accurate to a day listed in Hetherington’s Chronicle of Pre-Telescopic Astronomy (Wiley, 1996) is 22 October 2137 BC, when a total eclipse of the Sun was observed and recorded in the Shu-king in China. This is the eclipse that Hi and Ho famously failed to predict and got beheaded for. Which just beats the Babylonians, since there’s also a record of the eclipse of the Moon on 25 July 2095 from Ur.
It both cases, like Chronos, I presume that these exact days have derived from the particular eclipses being back-calculated, rather than being deduced from just the dating information in the records in question.

Incidentally, from my memory of the discussion of the issue in Scientists Confront Velikovsky, the Ammisaduqa-era Venus observations are a best-fit amongst several possibilities.