In imposing citizenship on the defeated Latins and Campanians following the Latin War, the senate’s principal object was not, as is sometimes asserted, to increase the number of recruits available for the Republic’s legions. Its aim, rather, was financial. Lengthy campaigns in Samnium were in prospect. These would require substantial increases in annual outlays for stipendium and other costs well above what had been usual when warfare had entailed briefer operations mainly within Latium. Those increases would in turn require significantly more tributum to be collected from the Republic’s assidui. The senators consequently faced a choice: they could greatly increase the tributum paid by each of the old citizens, or they could dramatically enlarge increase the number of tributum payers by turning many of the recently defeated Latins and Campanians into new citizens optimo iure or sine suffragio and thereby impose a lighter financial burden on each. The senate’s choice to distribute the greatly increased cost of future wars among many more assidui to a very great extent underwrote the long series of lengthy campaigns in Samnium and elsewhere after 338 that would gradually and inevitably establish Rome’s dominion over the Italian Peninsula.

An underappreciated difference between fifth- and fourth-century Rome was the emergence of stipendium and tributum (military pay and the land tax to fund it). Encompassing every citizen landowner and soldier, stipendium and tributum likely involved more people than any other civic institution at Rome. Moreover, this fiscal system changed the way in which Rome operated. It created a set of tasks that needed to be completed; it then instituted a new set of roles to complete those tasks; then it elevated a set of people in order to fill those roles; and finally those people developed new tactics to derive maximum benefit from their new functions. The key stakeholders in all this were the tribuni aerarii, who operated the system in local areas across the countryside. Though poorly attested in the extant sources, these men had the ability to control the smooth operations of the war machine. They promptly realized that they could hold the fiscal system hostage to extract political concessions. The exclusive rule of Rome’s patrician leaders, now reliant on plebeians to pay and collect taxes, was doomed.

This chapter examines the practical matter of resources in war-making, both human and material. The first half assesses recruitment practices across the course of Roman history, especially the role of conscription and compulsion, and then the changing size of military forces through time and its likely demographic impact. Consideration is also given to the logistical implications of the size of campaign armies. The second half focuses on the financial costs of maintaining the armed forces in the different periods of Roman history, before turning to the financial benefits of warfare, including booty, indemnities, territory and taxes – as well as the material costs of defeat. The quantitative dimension of all these subjects means that much of the discussion concerns the limitations of the extant evidence.