The rising importance of the new city accelerated the ruin of the old. From the time that Rome again became worth a contest, we find her citizens in arms, sometimes against each other, sometimes against the pretenders to the imperial crown. The spirit of feudalis, had distracted her inhabitants. Adalbert and Lambert, the Dukes of Tuscany and Spoleto, were invited to inflame the civil furies, and in the begining of the tenth century, Alberic, Marquis of Camerino, had obtained the dominion of Rome, and the hand of the famous Marozia. The expulsion of Hugo, king of Burgundy and Italy, the last of the three husbands of that “most noble patrician,” by Alberic the son of the first, and the repeated assaults of the city by the expelled tyrant, are not to be forgotten amongst the causes of dilapidation. The assumption of the imperial crown by the first Otho, in 962, and the revolts of the Roman captains, or patricians, with that of Crescentius, against Otho the Second and Third, had renewed the wars in the heart of the city, and it is probable had converted many of the larger structures into ruins or strongholds.

The next appearance of the monuments is when they had become the fortresses of the new nobility, settled at Rome since the restoration of the empire of the west. Some of these monuments were perhaps entire, but it is evident that some of them were in ruins when they first served for dwellings or forts: such must have been the case with the theatres of Marcellus and of Pompey.