"Regardless of their formal standing within this system, the one thing all involved parties had in common was the obligation to contribute military manpower under Roman leadership and to fund military operations: citizens paid a direct tax (tributum) specifically for this purpose while allied communities were expected to support their own levies. Scale and mobilization intensity were the two critical variables. Scaling-up was achieved by aggressive co-optation. Unlike in Greek city-states, where citizenship was often viewed as a prized privilege, Rome readily bestowed citizen status on outsiders, many of whom were defeated former enemies. Also unlike among the Greeks, citizenship thus became “divorced from ethnicity or geographical location.” The effectively oligarchic nature of Roman government appears to have sufficiently devalued citizen status to ensure this unusual openness. The fact that Romans who resettled in most colonies forfeited citizenship also reflects the relatively low value of formal membership in the Roman state. Allied polities retained their existing governmental arrangements and merely contributed military resources without being incorporated into the republic."