The patron saint of Lodi is Saint Bassianus, celebrated on 19 January: his remains are kept in the crypt of the duomo, the oldest part of the building. The town's gonfalon depicts on its reverse two scenes, one dedicated precisely to the patron, the other to Barbarossa handing over the insignia of the new Lodi to the town's notables.
The town ties its origins to the destruction of Laus Pompeia, an ancient Celtic village later a Roman municipium, razed to the ground by the Milanese in 1111 after a long siege, with a ban on rebuilding. Almost fifty years later, on 3 August 1158, Emperor Frederick Barbarossa refounded the town not on the ruins of Laus Pompeia, where today's Lodi Vecchio stands, but along the banks of the Adda, to ensure it a position of greater control over the territory, granting it extraordinary privileges. It was precisely that same day that construction of the duomo symbolically began, the town's oldest and most important monument, completed in 1284. In 1413 the Antipope John XXIII and Emperor Sigismund convened the Council of Constance from Lodi's duomo, which would resolve the Western Schism; on 9 April 1454 the Italian pre-unification states signed there the famous Peace of Lodi, which guaranteed forty years of political stability to the peninsula.
