If we go backwards in time using verifiable dates, what is the earliest event which can be associated with a specific day without question?

I am most interested in answers that actually show the chain of dates, not just an empty assertion (professor so and so said May 5, 2050 BC, is the earliest date...). For example, we know that the Inter gravissimas was issued on February 24, 1582, (old style) and that thereby October 4, 1582, was to be followed by October 15, 1582.

Therefore, given that in the Cronica Majora by Matthew of Paris it says that Harold Godwinson crowned himself king of England on the day that Edward was buried, which was "die Epiphaniae" (the day of the Epiphany, January 6th) in MLXVI Anno Domini. Since this was a date by the Roman calendar we can presume by the Gregorian calendar the event occurred exactly on the day 16 January 1066, 10 days later, assuming the Roman calendar used by Matthew was fully intact and continuous to 1582. Now, if you read any history book, such as the one cited by the Wikipedia, DeVries, K. (1999). "The Norwegian Invasion of England in 1066." (Woodbridge, UK: Boydell Press), it will say Harold became king on Jan 6, 1066, but we have just proved this is not true.

By this exercise we have shown that the dates you find in history books are often wrong. So, this brings us to the question again, going backwards from verifiable evidence what is the earliest event we can positively assign to a particular day. I have shown that we can assign the ascension of Harold to 16 January 1066, but I assume it is possible to go backwards much farther. The question is how much farther?

What is Meant by a Verifiable Date

By a verifiable date, I mean one where we can show absolutely the passage in time by days to the present day. For example, if the ascension of Harold occurred on January 16, 1066, and today is August 21, 2014, then we might think that the ascension of Harold took place 346461 days ago, or 948 years, 7 months, and 5 days ago. But is this really true? For example, if we consider that in 1066 the New Year occurred on April 1, not January 1st, then it is possible he ascended 949 years ago, not 948 years ago. An interesting question.

Aside from any calendar, how far back can we name the number of days to a particular event in history with confidence? Now, the person most expert at doing this was Joseph Scaliger, who invented the concept of the Julian Day for this exact purpose, and I am familar a little bit with some of the things he wrote, but since theoretically we have progressed in the last 200 years since Scaliger, I am thinking maybe someone has improved on his work. Hence the question.

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    You have miscalculated the Calendar correction in winter 1065-66; it should be only 6 days as the accumulated error of 10 days in 1582 includes errors (by the Gregorian Calendar) from the years 1100, 1300, 1400, and 1500. Thus Harold Godwinson crowned himself on December 31, 1065 Anno Domini (Gregorian). (en.wikipedia.org/wiki/Gregorian_calendar) Aug 21, 2014 at 22:13
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    It is universal practice of students of ancient and mediaeval history to use the Julian calendar to date events before the introduction of the Gregorian reform. The dates in history books are not “wrong”. All calendars are equally correct as long as you know which calendar you are using.
    – fdb
    Aug 21, 2014 at 23:05
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    I do not have the impression that you understand the difference between a calendar and an era. The Byzantine calendar IS the Julian calendar. But the Julian calendar can be used in conjunction with different eras (AD era, Seleucid era, Byzantine world era ...)
    – fdb
    Aug 21, 2014 at 23:20
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    I am afraid you are talking total rubbish.
    – fdb
    Aug 21, 2014 at 23:22
  • 3
    There are lots of very good books about calendars. You could start with “Calendars in Antiquity : Empires, States, and Societies” by Sacha Stern, 2012.
    – fdb
    Aug 21, 2014 at 23:27

2 Answers 2


I know this would not be to OP's liking (considering his expressed opinion of Chinese history), but other people might find this interesting.

The earliest event in Chinese history with a verifiable year is the Interregnum following the expulsion of King Li from the Zhou Kingdom. With the king exiled, his chief ministers ruled the realm in his stead. They declared the year, 841 B.C. , to be the first year (epoch) of the Joint Harmony era.

That event's significance is that it marked the beginning of consistent and preserved record keeping in China. The epoch changes with whenever the person on the throne changes - the Joint Harmony era terminated after 14 years, with the coronation of King Xuan becoming the new epoch. However, records were kept and added to year after year by every subseqeunt Chinese governement. Major events and government affairs were hence forth recorded by contemporary court historians in official annals - as opposed to being written down by a later historian.

Most of the early records have, unfortunately, been lost over time. The earliest annal in continuous survival is that of the State of Lu. Here is the year 722-721 B.C., from the State of Lu's official annals with rough translations:

    春,王正月。                         //Spring, January
    三月,公及邾儀父盟于蔑。              //March, pact made with the Baron of Zou
    夏,五月,鄭伯克段于鄢。              //Summer, May, Count of Zheng defeated his brother.
    秋,七月,天王使宰咺來歸惠公仲子之賵。 //Autumn, July, emissary from the King
    九月,及宋人盟于宿。                 //September, pact made with the Duke of Song
    冬,十有二月,祭伯來。               //Winter, December, the Count of Zhai visited.
      公子益師卒。                      //Lord Yi passed away.

    春,公會戎于潛。              //Spring, met with barbarians.
    夏,五月,莒人入向。          //Summer, May, Ju's lord visited
      無駭帥師入極。              //General Zhan attacked Ji.
    秋,八月,庚辰,公及戎盟于唐。 //Autumn, August, day of gēngchén, pact with barbarians
    九月,紀裂繻來逆女。          //September, bridal escort arrived from Ji
    冬,十月,伯姬歸于紀。        //Winter, October, princess leaves for Ji
      紀子帛莒子,盟于密。       //Barons of Zi and Ju allied
    十有二月,乙卯,夫人子氏薨。  //December, day of yǐmǎo, the Duchess passed away.
      鄭人伐衛。                 //Zheng attacked Wey

Of special interest are the August and December entries (Lu's pact with the barbarians, and the death of Lu's duchess), which specified the dates. As far as I know, these are the earliest events in Chinese history that have verifiable exact dates.

Note that these records are made in the traditional Chinese calendar, but that can be of course be converted to Gregorian dates.

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    The problem of course is manuscripts written long after the supposed events. The wiki claims that there exists a 5th century mss of the Records of the Grand Historians without citing. Just even knowing what this mss is, I guess I would find pretty interesting, since all the Chinese originals I know of are much later than that. Aug 22, 2014 at 15:05
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    Also, let's for the sake of argument suppose we have a 5th century mss and it gives a 722 BC date. Are you claiming that the calendar used was never altered and was continuous to the 5th century, and to the present time? This seems kind of unbelievable to me. I had thought the Chinese used regnal years, which would make it impossible to locate a date straight off the bat because of uncertainty when a particular ruler died or came to the throne. Even in Europe regnal years cannot be used for precise dates without additional corroboration. Aug 22, 2014 at 15:13
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    The Chinese calendar names each year using a combination of specific characters that repeats every 60 years. Regnal years, and later era names, are imposed upon this system. The combination identifies the precise year in question, because given that records are continuous on a yearly basis, it is exceedingly unlikely to misidentify a reigning emperor by an error of 60 years.
    – Semaphore
    Aug 22, 2014 at 15:26
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    @TylerDurden Still waiting for your ludicrous claim to be backed up by something other than "the completely baseless opinion of @TylerDurden". You can ask about Shiji in another question.
    – Semaphore
    Aug 22, 2014 at 18:23
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    @TylerDurden Nice try at baiting, but I'm still not biting. Again, if you want to ask about Shiji make it its own question: it is completely irrelevant to my answer no matter how much you clearly wants to change topics to avoid admitting being hopelessly wrong. The fact is once again, you prove incapable of providing a single shred of evidence to support your ridiculously unscientific and outlandish claims that are painfully obviously rooted in ignorance. Dress up your self-righteous arrogance all you like, you are still only making unsubstantiated claims with no evidence whatsoever.
    – Semaphore
    Aug 22, 2014 at 18:38

There are lots of documents in Sumerian and Akkadian with precise dates mentioned in the documents themselves. These go back well into the 3rd millennium BC. These can be converted without difficulty into Julian or Gregorian dates.

But of course, all this depends on what you mean by “events”. If you include astronomical events visible on earth (eclipses, novae etc) then these can be dated down to a fraction of a second by astronomical science; this will take you back millions of years.

  • Ok, if it is so easy, demonstrate it. My question asks for historical events, not astronomical ones. If you want to try to prove a date using an astronomical event, that is fine with me, so long as the date being proved is a historical day on which something historical happened. Aug 21, 2014 at 23:17
  • An eclipse is "something historical".
    – fdb
    Aug 21, 2014 at 23:38
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    Enjoy: en.wikipedia.org/wiki/Eclipse_of_Thales Aug 21, 2014 at 23:59
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    @congusbongus Well, you certainly have given the best answer so far to my question. I do know about this eclipse. The problem is that there is a lot of ambiguity of whether Herodotus' eclipse is the same one as the NASA suggested eclipse. If you read the wiki article you can see they recognize this. If you look at eclipse charts you can see that there is uncertainty. I actually have a reference book on EVERY historically referenced eclipse. The trick though is that they all have a certain amount of ambiguity unless combined other info, which is where it gets complex. Aug 22, 2014 at 1:34
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    Let me add that there are many Babylonian tablets recording astronomical observations on specified dates. These can be checked with modern methods. Ptolemy’s Almagest (2nd century AD) records many of his own observations with the day and month of the Egyptian calendar and the year according to the era of Nabonidus. These too can easily be verified. All of this is long before the year 1000.
    – fdb
    Aug 22, 2014 at 12:56

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