4,000 years ago the Scottish were most likely people of color!
https://www.livescience.com/archaeology/see-the-amazing-facial-reconstruction-of-a-bronze-age-woman-discovered-crouching-in-a-4200-year-old-grave
I wrote most likely, because they didn't have the woman's DNA so they had to make educated guesses about many of her features.
I have to admit, I was a little surprised seeing that story, but it makes sense. I think those people of color most likely had been conquered and murdered or pushed out by white people. Imperialism is deeply rooted in white cultures, after all.
Or could they have evolved to look more like the majority population of Scotland today in something like 2,000 - 3,000 years? (History and art from 1000 + years don't really describe them as people of color.). I'm not a biologist, but that doesn't seem like enough time.
The article doesn't give all the answers! Nice work by these scientists and anthropologists, though.