Were the Egyptian pyramids built by slaves?
The labourers would have been enticed by the mix of high-quality food and the opportunity to work on such a prestigious project. Today, many of the highly experienced archaeological workmen at the pyramids come from the same region, though they are paid in hard currency, rather than prime beef and accolades.
The Pharaohs were large plantation owners with enormous surplus foodstuffs, including livestock and garlic (which was highly prized for its medicinal value). And the workers were, in many ways, members of an enormous enthusiastic cult community that rewarded the construction of these mega-projects both economically and socially.
So, not all that far off from capitalism in the modern sense.