Caesar in his Bellum Gallicum -- the gauls had cities (that Caesar's army had to build siege engines to take) and kings. The regions had millions of people livi

Caesar in his Bellum Gallicum -- the gauls had cities (that Caesar's army had to build siege engines to take) and kings. The regions had millions of people living there. In one tribe alone (Atuatici), Caesar, to punish them sold 53,000 people from a single tribe into slavery. This isn't the entire population, just what he could round up in a single town. I don't think small tribes of wandering hunters with small farming plots can sustain that many people. Caesar ran around and laid sieges to these things regularly during the Gaullic Wars. https://en.wikipedia.org/wiki/Oppidum https://en.wikipedia.org/wiki/Oppidum