The Sommariva family has been part of the history of Lodi since its origins: an Archimbaldo was part of the group of Lodi consuls who received the investiture from Emperor Frederick Barbarossa on the Eghezzone hill on 3rd August 1158, following which the foundation of the new city began.

The palace, imposing in its construction -- a work of the 17th and 18th centuries -- retains its ancient splendour with a beautiful portal surmounted by a wrought-iron balcony.

The symmetry of the ground and first floor windows mellow the façade and lend it nobility and lightness. The interior, although remodelled, still retains a sumptuous hall of honour with a vault decorated with fine Baroque stucco decorations. The recently restored interior rooms have numerous frescoes that were thought to have been irretrievably lost. During the 'French' era, the building was the seat of the Commissariat and it was here that Francesco Melzi d'Eril (the future Duke of Lodi) handed over the keys to the city of Milan to Napoleon (11th May 1796), after the French troops' victory the day before at the bridge of Lodi.

A plaque on the façade commemorates the historic event.