Geoffrey of Monmouth's History of the Kings of Britain makes similar claims for Scythian ancestry, and that the Scythians were in turn refugees from Troy.

He also claimed that ancient Britons laid seige to Rome.

Pretty funny how his bullshit survived and was repeated through the centuries.

And on the way from Scythia the Scots somehow also apparently also picked up the stone that Jacob rested his head on at Bethel which became, via a detour to Dunadd and Scone, the Stone of Destiny!

[Spoilsport geologists dispute this story with their pesky "facts" ;-)]

It's not an unreasonable legend. Conventional wisdom is that all Indo-Europeans sprang from the steppes of Central Asia. Having it mentioned in a 14th century declaration is pretty fascinating!

Given the context of the Declaration (i.e. The First Scottish War of Independence) it sounds to me like propaganda trying to claim an ancient and separate lineage for the Scots.

Mind you the Declaration is a great document - proclaiming Scottish freedom and saying that while Robert the Bruce is a cool guy if he doesn't turn out to be a good king then he'll be sacked and another one found from somewhere. Which is a fairly novel idea for kings.

The proto-indo-European migration is thought to have been a cultural and linguistic migration, not a mass physical migration or a conquest.

Source on that? IE spread from the Dnieper River area to Western Europe and Western China in a rather short amount of time. Clearly there was a lot of migration from the Urheimat.

Sort of. The languages did. But there were people in Scotland before any indo Europeans got there.

And people before those people, most likely!

That is was written in the 14th century makes it very suspect.

The legendary early settlers of Ireland, the Nemedians (who would have later settled Scotland) came from Scythia:

"Nemed, ... was the son of Agnoman of Scythia..."

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

Interesting that they talk about their predecessors completely dying out. There was a fascinating Time Team special where they mentioned that Britain has had seven completely separate waves of inhabitants - with the predecessors apparently all dying out.

Probably a coincidence though as the timescales won't match up but fascinating to even consider that there was some historical truth behind those old myths.

Sounds similar to the stories of the deluge in many cultures, that supposedly wiped out all or most earlier life, once or periodically. Bible's Noah's ark, Hinduism's pralaya (IIRC, primeval flood), many others ...

If there really was such a thing, it might explain a lot of these stories.

I was astonished to learn that the biggest Celtic megalith structures are in northern France. Easy to forget how certain empires spread and collapsed in different directions.