Half Rome’s budget at end 4th century went to feeding & paying the army of about ½ million.
Logistics of army supply was the single most important element that linked the imperial provinces together, along with the need to feed the imperial capitals.
Imperial Tax System
Underpinning all these structures, and making them possible, was the imperial tax system, which was based above all on a land tax, assessed on acreage, through buttressed by a much lighter tax on merchants and artisans.
High taxes were needed for several reasons:
- To pay the salaries of soldiers, bureaucrats and messengers.
- To feed the capitals of the empire.
- To fund the enormous scale of Roman public buildings and state wealth.
- To connect the different parts of the empire together physically, as grain in ships moved northwards from Africa, Sicily and Egypt, and olive oil moved out of Africa, the Aegean and Syria. The movement of goods was essentially Mediterranean-based, as it was far easier and cheaper to transport in bulk by water than by land.