Blazon: Gules a cross argent, a label of three points azure
This is actually pretty straightforward, as Italian arms go. Gules a cross argent are the arms of the house of Savoy; in 1424, Duke Amadeus VIII of Savoy granted his oldest living son (also named Amadeus, because of course) the title Prince of Piedmont. And, as the eldest son, Amadeus bore the arms of his father with the traditional label for difference. There have been slightly different configurations of the arms over the years (mostly adding, removing, and changing the tincture of bordures), but the cross and label have remained consistent.