These prisions, located on the ground floor of the Palazzo, are separated into two areas: the female and male public prisons.
In reality, to this day we don't know exactly whether the prisons occupied the same spaces in the 15th century as they do today. In all likelihood, the process of forming the prison complex was a fairly long one, spanning three centuries, from the 15th to the 18th century. Certainly, the prisons must never have looked very different from their present-day counterparts, as the Florentines were forced to use a fairly restricted and already "characterised" space, with very thick load-bearing walls, in which it was difficult to make doors or destroy walls without jeopardising the entire stability of the building. There are currently three cells, facing a corridor that also provides access to the latrines. Once inside the Prisons, one notices the considerable height of the ceilings, not very appropriate for a medieval prison.
In fact, the prison was used from the 15th century onwards, but it should not be forgotten that we are inside a building constructed in the 12th century for an entirely different purpose, so that the subdivision of the internal spaces was that of a civil domus and had no public function, as the Palazzo would assume from the 15th century onwards.
It is not difficult to imagine that the living conditions in the prisons between the 15th and 17th centuries were not at all easy, and some 17th-century documents preserved in the local Historical Archives give a description of the cells in which the miserable state the prisoners were forced to endure is very clear from the plan attached to them: there was no light or air exchange, there were no toilets, but a common hole in the first cell was used, and there was no possibility of heating, so they were forced to light a fire in the middle of the room, but since there was no chimney the room quickly filled with smoke (even now you can see a strong presence of soot under the first eighteenth-century whitewash).
The current appearance of the prisons is due to the modernisation work carried out from the 18th century onwards, which gave them a more humane appearance.