The Casa di Correzione (house of correction) of San Michele a Ripa opened in Rome in 1703. It was a prison with a cellular structure that was exclusively reserved for minors, wherein the concept of punishment went hand in hand with that of rehabilitation. This was to be achieved through work and a disciplined life based on isolation at night and silence during the day, which the inmates spent together. These elements were later developed in the context of enlightened criminal reforms, and were for the first time brought together in an architectural structure conceived for that specific purpose. It is therefore understandable that at the end of the century John Howard, one of the most important spokesmen for criminal reform, was so impressed by his visit to the Casa di Correzione that he wrote on the title page of the second volume of his work on European penal institutions1 the “admirable sentence” that he had read inside:

The most characteristic and original aspect of the Casa di Correzione was its architecture (see Figure 16.1). Designed by Carlo Fontana, the greatest Roman architect of the time, its nucleus was composed of a single large rectangular locale (central hall) that was 42 meters long, 15.55 meters wide, and more than 14 meters high. This space was covered by a high barrel vault; it was lit and aired through two large windows located in the middle of the longest sides and three smaller ones on the shortest sides, as well as through six large holes along the sides of the volta.