So, here are a few facts we know about Ancient Nord History:

• Atmorans / Proto-Nords crossed over to Northern Skyrim throughout the late Merethic Era (possibly as early as ME1000). At this time Skyrim was inhabited by Snow Elves/Falmer (and also the Dwemer).

• Following a massacre at the Proto-Nordic city of Saarthal by Snow elves, the Atmoran hero Ysgramor led 500 warriors to Skyrim to take revenge against the elves. Ysgramor founded the city of Windhelm, conquered large parts of Skyrim, and he and his descendants went on to all but eradicate the Snow Elves.

• King Harald, who is “13th in the line of Ysgramor”, united Skyrim into a centralised Kingdom. He was the “First High King” of Skyrim, ruling from the 143rd to the 221st year of the 1st era. He was 108 years old when he died.

The question is: When did Ysgramor invade Skyrim? We don’t have any clear dates, but here are my thoughts:

We have exact dates for the reign of king Harald, and we know that he was the “13th in the line of Ysgramor”, presumably meaning he was the 13th king of the Ysgramor Dynasty. So all we need to do is estimate the average length of reign for a King of the Ysgramor dynasty, and multiply by 13 to get the time difference.

But that’s not necessarily 13 generations, just 13 kings/rulers. Oftentimes in ancient and medieval dynasties the throne doesn’t pass cleanly from father to son. Sometimes it will be inherited, or seized, by a brother, uncle or cousin instead.

And we can’t assume every individual king had a long, stable reign. Some might only reign for a few short years or even months, especially in unstable times. I’d assume this period was overall pretty chaotic and unstable, with major demographic shifts, climatic collapse in Atmora, and bloody wars against both elves and dragons (whom we’ll get to later). I wouldn’t be surprised if a few of those 13 rulers had pretty short tenures. Harald’s remarkable 78-year reign is longer than any (verifiable) monarch in real-world history. In real history, even a 30-year reign is considered long and stable. I think it’s safe to assume that the average reign of the members of the line of Ysgramor (Excluding Harald and Ysgramor themselves) would be relatively short.

I think the average might be below a decade, but I’m going to be very generous and place the average reign at 15 years. So, if Harald came to the throne in 1E 143, and there were 11 kings between him and Ysgramor (Ysgramor being the 1st and Harald being 13th), each of whom reigned for an average 15 years, that places the end of Ysgramor’s reign some 165 years before the ascension of Harald, and 22 years before the end of the Merethic Era / start of the First Era. (again, that is being seriously generous with the average reign length).

We don’t know the length of Ysgramor’s reign, but we know he already had two adult sons when he first invaded. This would mean he was at least around 40 years old at this time, if not older. We also know he apparently had a long and successful reign (although most stories about Ysgramor are so muddied by millennia of myth and legend it’s hard to say for sure). Assuming he didn’t live much past 100 years old, this would place the absolute upper limit of his reign at about 60 years. Obviously a shorter reign is more likely, but again I’m being generous. This would mean Ysgramor’s invasion started, at the absolute earliest, 82 years before the start of the first era.

This all works out ok, 80-ish years seems an ambitious but not unreasonable amount of time for the Nords to establish rule over the whole province and to mostly wipe out the Snow Elves. But the timeframe starts to fall apart when we consider another facet of Ancient Nord history: the conflict with the Dragons. Because the Nords were’t really the one’s ruling Skyrim at this time.

(Ramble continues is comments)