> The proportion of enslaved people in mid 1700s South Carolina about 3 to 5x that of ancient Rome. And even that's nothing compared to the Caribbean.
You are picking a very specific area and comparing it to the entire Roman empire? The proportion of the population that was enslaved was significantly higher in Italy than in the rest of the empire (and it was about on the same level as in the Southern States by 1860, around 30-35%).
I can't find reliable figures but it was significantly higher in Sicily and Southern Italy and probably as high if not higher than in South Carolina.
> Sell it to their neighbor, who is also a farmer and grows all the same things?
No but there was still extensive trade on the regional level. Not by modern standards of course since surpluses were very low (but not by Roman standards since productivity had likely increased significantly throughout large swaths of the former Roman empire due to technological progress). e.g. the production of wool which was exported to the low countries made up a non insignificant fraction of the English economy.
> significant cash crop economy in medieval Europe.
I think people often tend to compare Northern and Western Europe during the middle ages with the Mediterranean centered Roman empire for some reasons. I'm not sure there was an extensive crash crop economy was particularly more extensive in Northern Gaul, Germany or Britain during the Roman period (probably the opposite since the population sizes seem to have been much higher in those regions during the middle ages).
The plantation/latifundia based economy in Southern Italy had collapsed of course but I'm not sure that the production of main cash crops wine/olives was necessarily much lower overall by the high middle ages even in Southern Europe (though of course it varied by exact period and region).
You are picking a very specific area and comparing it to the entire Roman empire? The proportion of the population that was enslaved was significantly higher in Italy than in the rest of the empire (and it was about on the same level as in the Southern States by 1860, around 30-35%).
I can't find reliable figures but it was significantly higher in Sicily and Southern Italy and probably as high if not higher than in South Carolina.
> Sell it to their neighbor, who is also a farmer and grows all the same things?
No but there was still extensive trade on the regional level. Not by modern standards of course since surpluses were very low (but not by Roman standards since productivity had likely increased significantly throughout large swaths of the former Roman empire due to technological progress). e.g. the production of wool which was exported to the low countries made up a non insignificant fraction of the English economy.
> significant cash crop economy in medieval Europe.
I think people often tend to compare Northern and Western Europe during the middle ages with the Mediterranean centered Roman empire for some reasons. I'm not sure there was an extensive crash crop economy was particularly more extensive in Northern Gaul, Germany or Britain during the Roman period (probably the opposite since the population sizes seem to have been much higher in those regions during the middle ages).
The plantation/latifundia based economy in Southern Italy had collapsed of course but I'm not sure that the production of main cash crops wine/olives was necessarily much lower overall by the high middle ages even in Southern Europe (though of course it varied by exact period and region).