The Civic Museum of Alatri , established in 1932 at Palazzo Conti Gentili and reopened to the public in 1996, is currently located in the restored halls owned by the municipality in the thirteenth-century Palazzo Gottifredo. The aforementioned Palazzo represented the reference architectural model for many noble residences in the medieval city. It dates back to the mid-thirteenth century and was built by Cardinal Gottifredo Raynaldi, a wealthy Alatrense feudatory and learned papal diplomat, as his residence during the years of the anti-imperial struggle. tower-house (certainly older than the rest of the building), on the corner between Corso Vittorio Emanuele and Via Cavour, a central body located along the main street and, finally, behind the latter, another tower.
With a trapezoidal plan, the Acropolis of Alatr i due to its size, two hectares of area and entirely visible along the approximately 600 meters of perimeter along the Via Gregoriana, the proportions and dimensions of the individual blocks, represents one of the most significant examples of polygonal walls. The important excavations directed by the Superintendence for Archaeological Heritage of Lazio between 1976 and 1979 have brought to light, in the area behind the so-called "Sanctuaries", a polygonal base and some finds that indicate its probable function as a place of worship , and that in some specimens they should go back at least to the fifth century. B.C. This would prove that a first fortification on the top of the hill occurred at least in the late Archaic period.