Who forced payments to Romans usually in grain?

Payments to the Romans, often in the form of grain, were typically enforced by local rulers or client kings in provinces under Roman control. These leaders were expected to maintain order and ensure the collection of taxes for the Roman Empire. Additionally, Roman officials and tax collectors, known as publicani, played a significant role in imposing these payments on local populations. This system was part of the broader Roman taxation structure that supported the empire's economy and military.