Also worth mentioning was the consolidation of small free-held farms into large estates held by senators and run by slaves.

This consolidation was partially driven by war debts; Roman citizens accrued debts during the wars of conquest, while the generals won the spoils with which they could purchase the land of indebted citizen farmers. It was also driven by economies of scale; the larger estates were more efficient, had lower costs of operation, and had the market contacts to grow the crops that generated the best profit when shipped.

Of course this means Italy basically stopped making food when senators could sell oil at higher margins, and began to depend on Sicily and Egypt to produce the grain for Rome, with the latter eventually becoming the personal property of the emperor. This would cause serious problems later, but the senators profiting neither knew nor cared.