The Romans met their match in Scotland. They built Hadrian's Wall in northern Britan to keep the "barbarians" away from them. A bunch of fur wearing heathens scared them silly.
Rome fell to internal rot. Anyone see the comparision with what the US has today?
About 20 years after building Hadian's wall, the Romans pushed a bit further and built the Antonine wall, constructed with earth band stone, along with added wooden structures.
However, they could not hold the position, so they abandoned the Antonine wall at about 158-160 AD. Curiously, there were many iron nails left over, perhaps from the blacksmith shop or from burning the existing buildings.
Not wanting the native Scots or Picts to get the iron to make arrowheads and other weapons from them, they buried hundreds of pounds of those nails.
About 20 years ago, archaeologists dug up those nails. I bought 3 from them, mounted in a small terra cotta "house".
I have a historic souvenir, and archaeology has a donation toward their work. Some claim Rome left the highlands, because there was no plunder available..and plenty of pain if they tried to invade.
Here is a song you will enjoy..pay special attention to the lyrics
https://www.youtube.com/watch?v=GowMI4wvmU4