Here is information from a previous post.
Ancient Roman historians declared that the founding of Rome was on the specific date of 21 April 753 BCE, but I’d not classify that as confirmed. Other earlier Roman events were recorded with progressively more plausible confirmations, so depending on your definition of ‘confirmation’ probably your earliest date would be somewhere between the almost certainly fictional founding date and the very well confirmed assassination of Caesar (15 March, 44 BCE). The campaigns against Hannibal, for example, were recorded in detail by contemporary historians and some events there could reasonably be considered confirmed dates.
Back-calculating from astronomical events is sort of different than answering this question with actual historical sources, but which probably comes down to what you consider ‘historical’. Roman histories have the advantage that their system of calendar survived and dates can thus be easily translated.
The old Roman method of dating was based on Consuls, which was an office distinguished men were appointed to for a year. So an event would be described as having happened in the Year of the Consulship of Crocettius and Levitchus. And there would be publicly displayed list of past consuls so people would know the order.
The problem was that being named as a Consul was a prestigious honor and indicated your family was important. And families that grew in power later on would want to create the impression that their family had ancient roots. So they would make up fictional ancestors and add their names to old consul lists.
Well, that was one method of dating, and the one more often used in practice. But they also had numbered years, much like we do, dating from the (purported) founding of the city.
We still use a regnal-year date system. It’s just that the king involved happens to be immortal…
How far back are historical calendars accurate without regard to astronomical pinning? The death of Julius Caesar was mentioned; how much further do Roman records extend such that we can be sure that a day hasn’t been unknowingly skipped or added? How about calendars from Greece, China, Egypt, etc?
I took a college science course; one instructor said that Egyptian inscriptions indicated some historical event taking place when Vega was the polestar ( instead of Polaris ). He said that, calculating the procession of the earth’s axis, that meant that the event occurred 25,000 years ago. So he said.
Huh. So, you’re all saying its not 9/11?
That’s (about) the time for a full period of precession, the time when alpha Ursa Minoris would previously have been the pole star. For Vega being the pole star is only about half of that.
His point was that they might lie and say that he was born the day that they spotted Venus, because that would tie the birth to something auspicious.
We would know when the spotting of Venus was but still not know when the Emperor was born. They wouldn’t falsify the astrological observation, they’d falsify date of the birth.
Only if the records said, “The Emperor was born - no auspicious/negative astrological symbols”, could we trust that the records were honest.
Though, the astronomical observation would still have to be plausibly close to the birth. It probably fixes the date with more accuracy than anything else.
Which explains my skeptical phrasing.
But real Egyptian civilization started much later. There are indications of agriculture in Egypt and Mesopotamia from about 10,000BC, but actual heirglyphics and inscription art start with the beginning of the Old Kingdom, about 3,000BC or closer. There are some surviving rock carvings from southern oases, IIRC, from about 5,000BC. But all in all, nothing explicit that give astronomical details from 12,000BC or 10,000BC.
During the Old Kingdom period when the pyramids were being built, the pole star was Thuban, a fairly dim star in Draco. Dimmer than Polaris, anyway, although easily visible in those less light-polluted times. It was closest to the pole about 2830 BCE, and would have been considered the pole star for about 500 or 600 years on either side of that date. I suspect that the instructor’s info on the Egyptian pole star was a distortion of a reference to Thuban getting confused with Vega being the pole star much earlier.
BTW, Polaris has been considered the pole star for about the same length of time (500-600 years). Despite its name being from Latin, it only received it in the fifteenth century. If you go back to the Roman Empire era, there was no good pole star, just as there is no good one for the South Pole today.
This image shows the precession of the north pole against the night sky over its 26,000 year period. The only problem it has is that it doesn’t allow for proper motion of the stars. So it’s not perfect; stars may move relative to that circle from one time around to the next.
According to Uberfacts:
Allegedly, the royal astronomers were the two drunks in this case.
I think that was Hsi and Ho–whom the emperor ordered executed for their dereliction of duty.