Gian Giacomo and his collection had a big political role. He was a nationalist at a time when there was no Italian nation. His love for the Italian Risorgimento's ideals is shown by his active participation in the rebellion of the Five Days which sparked the First Italian War of Independence. With the other Milanese nobles, he bought an artillery command for the Lombard army and subsidized the Piedmontese army. In 1848, he obtained an official role, although not prominent one; he was sent to Venice as Special Commissioner of the Provisional Government of Lombardy in the Venetian provinces.