Ergastulum

An ergastulum (plural: ergastula) was a Roman building used to hold in chains dangerous slaves, or to punish other slaves.^[1] The ergastulum was usually subsurface, built as a deep, roofed pit - large enough to allow the slaves to work within it and containing narrow spaces in which they slept. They were common structures on all slave-using farms (latifundium).^[2] The etymology is disputed between two possible Greek roots 'ergasterios' (workshop) and 'ergastylos' (pillar to which slaves were tethered).

The ergastulum was made illegal during the reign of Hadrian, as part of a series of reforms to improve conditions for slaves.^[3]

Columella in his Res Rustica^[4] states that for slaves kept chained in the underground ergastulum it should be as healthful as possible and be lit by windows with narrow bars which are far enough from the ground that it is not possible to reach them by hand.^[5] In the Loeb Classical Library 1941 edition^[6][7] H. B. Ash translates a later section in Book 1, Chapter 8 of the Res Rustica as: "Again, it is the established custom of all men of caution to inspect the inmates of the workhouse [ergastuli^[8]], to find out whether they are carefully chained, whether the places of confinement are quite safe and properly guarded, whether the overseer has put anyone in fetters or removed his shackles without the master's knowledge.^[9]" Ash translates the term ergastulis as "chain-gangs^[10]" upon its first appearance in the Res Rustica in Book 1, Chapter 3.^[11]

The term is also used to describe any small Roman prison.

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