Spolia lapidei a Milano tra Tardo Antico e Medioevo: dinamiche costruttive e problemi aperti

The election of Milan as the capital of the western part of the Roman Empire (286-402 A.D.) brought about a transformation with strong urban and architectural connotations, of which important monumental evidence is still preserved. Among those dating back to the early period of Late Antiquity, as far as public buildings of a civil character are concerned, one can count above all the extension of the city walls, the building of new large baths, the construction of the Imperial Palace with an adjoining circus. From a construction point of view, all of this entailed the massive use of stone material from more ancient buildings and necropolis areas. Later, in a more advanced phase (second half of the 4th-6th centuries), with the transformation of Mediolanum into a Christian capital, the phenomenon of stone, but also brick, reuse spread widely, with different distribution criteria connected to the new market for building materials. Many aspects of the dynamics of this process remain to be clarified, not only in relation to the centre under analysis. In this chronology, therefore, with the exception of the section reinforcing the city walls attributed to Narses (mid-6th c.), stone spolia flowed mainly into the building of the new cult poles, the most monumental and well-known of which is certainly the great complex of San Lorenzo Maggiore (late 4th - early 5th c.), the foundations of which contain, among other things, thousands of cubic metres of building elements from the amphitheatre converge. In this regard, if the traceability of the phenomenon of stone reuse is thus proven in that specific case, it is much less so in the other religious foundations which, at the end of the 4th century, are mainly connected to the commissioning of bishop Ambrose, the shaper of the new Christian topography of the city. If, during the Late Antique period, a certain continuity in the distribution of stone spolia in urban building sites is observed, in the following centuries and up to the beginning of the Late Middle Ages, discontinuities of attestation are instead found, probably connected to economic downturns in the building sector.