The linked article says: >Imprisonment was not a sentence under Roman statutory law,[2] though detention is mentioned in the Twelve Tables and throughout the D

The linked article says: >Imprisonment was not a sentence under Roman statutory law,[2] though detention is mentioned in the Twelve Tables and throughout the Digest.[3] "Detention", however, includes debt bondage in the early Republic;[4] the wearing of chains (vincula publica), mainly for slaves; and during the Imperial era a sentence of hard labor at the mills, mines or quarries.[5] Slaves or lower-status citizens sentenced to hard labor were held in prison camps.[6] >Incarceration (publica custodia) in facilities such as the Tullianum was intended to be a temporary measure prior to trial or execution; abuses of this principle occurred but were officially censured.[7] Located near the law courts, the Tullianum was used as a jail or holding cell for short periods before executions and as a site for executions. So yes, as I said, imprisonment is a newer development. Holding people temporarily is jailing. Imprisonment, in the "sentenced to prison for a period of time or indefinitely" is a modern idea. It was considered barbaric by some cultures historically, but it also was just not viable. There was a small surplus of food, which was for the aristocracy to siphon off the top (ostensibly to fund the defence of the realm), not for feeding common criminals.