The cryptoporticus with its fresco decoration dating back to the I-II century A.D., was discovered under the Villa Boncompagni Ludovisi in Rome in the area of the ancient Horti Sallustiani, where the U.S. Embassy now stands. The cryptoporticus (see description in section “Wall paintings”) underwent restoration works first involving environmental and wall rehabilitation, then the installation of a microclimatic monitoring system to measure the temperature and relative humidity. Continuous monitoring of the temperature and humidity range was observed for several years, as swift surges in these values might cause new salt formations or other detrimental biological attacks. Programmed maintenance works on the frescoes have since been carried out such as the total removal of superficial patina in addition to several preventive biocidal treatments on the whole surface.