With the “setting” of the Roman Empire, noble roman families took procession of the complex’s various buildings. The split ownership and subsequent works transformed the Market into the robust Miliciae (fortification).
The powerful Pope Boniface VIII came into procession of the structure in around 1300 but did not keep it for long despite the huge resources he sunk in.
Next Arrigo VII, who was crowned emperor in the Lateran Cathedral, made the complex his headquarters in 1312 and lodged troops there to make full use of the Milizie tower. The tower was initially built entirely using the tufelli technique between 1200 and 1250 and at a later date between 1250 and 1280 it was faced in the bricks still visible today.
By then the heavily damaged Great Hall was renamed Thermae de Paliariis probably due to the presence of exposed downward sewage pipes.
The reconstruction of sections of the outside walls of the central section with different materials and the loss of its terminal section testify to the complexes’ ruin. The destruction may have been caused by the earthquake of 1349 but damage was doubtlessly made worse by years of prior neglect. In some 15th and 16th centenary drawings the Great Hall appears without its outer walls, whilst the Great Hemicycle is partially broken. What remained of its decorative brick façade inspired the architects of the Renaissance in the building of new noble palaces.