This paper is a historical outline of the practice of reuse in Rome between the 4th and 13th century AD. It comments on the relevance of the Arch of Constantine and the Basilica Lateranensis in creating a tradition of meanings and ways of the reuse. Moreover, the paper focuses on the government’s attitude towards the preservation of ancient edifices in the monumental center of Rome in the first half of the 5th century AD, although it has been established that the reuse of public edifices only became a normal practice starting in 6th century Rome. Between the 6th and 8th century the city was transformed into settlements connected to the principal groups of ruins. Then, with the Carolingian Age, the city achieved a new unity and several new, large-scale churches were created. These construction projects required systematic spoliation of existing marble. The city enlarged even more rapidly in the Romanesque period with the construction of a large basilica for which marble had to be sought in the periphery of the ancient city. At that time there existed a highly developed organization for spoliating and reworking ancient marble: the Cosmatesque Workshop.