Roman VAT

I have a Scottish upbringing. Maybe that’s why I am sceptical of glib explanations. I’m told the Roman legions, with their shields making a tortoise to cover them from rocks or spears or arrows fired at them were terrified of the Scots and particularly the Picts of the Western Highlands and that is why they ran back and cowered behind Hadrian’s Wall. I can’t see either that, or the tale of the Picts gathered together a great army. The Picts were a mixture of McDonalds and Campbells and McLeans and Macbeths, all stealing and squabbling among themselves, so what really happened? The Roman’s found tin in the south, then copper further north, then lead, zinc, a bit of silver and some gold in southern Scotland and that explains Antonine’s wall to protect that. What happened then was that the money men in London complained about the cost of the lead etc. it was costing. The agents explained they paid for the stuff in Scotland but the couriers got robbed in the border country and it all had to be bought back from the robbers at Hadrian’s Wall. At that point the London men sent word to pull back to Hadrian’s Wall and buy from whoever brought the stuff. If it was the producers, fine. If it was the robbers, that’s life. Now, that seems are more likely explanation than the legionnaires being terrified of a bunch of naked, blue painted screaming savages.
Since the gates in the walls were also places where duty was collected, it may be that there was too much smuggling across the firth of Clyde (unlikely what?) and it was easier to control at Hadrian’s Wall. Which means that sales tax started with the Romans and even in 43AD, there was no escaping VAT.