Rome conquered most of its territory when it was a semi-democratic republic. The Roman republican government was more popularly legitimate than many of its cont

Rome conquered most of its territory when it was a semi-democratic republic. The Roman republican government was more popularly legitimate than many of its contemporaries. Even the early Roman emperors were quite weak within Roman society. It was not a dictatorship, although it became moreso over time. The Roman tax system used delegation, where tax collectors were given a territory and a target, and any revenue over the target could be kept by the official. And as motohagiography points out, the military as a bare-bones state can be sustained with continuous conquest where the potential spoils of conquest are used to gain military allegiance. It's not a coincidence that the Roman Empire entered a period of crisis, that proved terminal, after it stopped expanding.