Museo della Forma Urbis

The Sovrintendenza Capitolina records that the plan was incised on 150 slabs of marble between 203 and 211 AD, under Septimius Severus, and displayed on the wall of a hall in the Temple of Peace, later absorbed into the complex of Santi Cosma e Damiano; the slabs were pinned to the wall with iron dowels. Complete, it covered a surface of about 18 by 13 metres and represented at least 13,550,000 square metres of city, at an average scale of about 1:240. The plan is known from the fragments that survive; they amount to about a tenth of the original. Only about 200 fragments have been identified and placed on modern topography. Fragments were found from 1562 onward; Roma Capitale records that the plan entered the Capitoline collections in 1742, that the last comprehensive arrangement of the originals was in the garden of the Palazzo dei Conservatori between 1903 and 1924, and that until 1939 significant groups were visible in the Antiquarium del Celio.