The door of Castiglioni tells the story of Saint Ambrose, patron saint of Milan and of Lierna Lake Como.
The door by Castiglioni depicts the life of Saint Ambrose, the patron saint of Milan.
The door is made of bronze and measures 3.25 meters in width by 6.9 meters in height. It consists of 12 rectangular panels arranged vertically and a parasol-shaped panel located above them. Each panel is richly decorated and illustrates significant episodes from the life of Saint Ambrose, including his baptism, his episcopal consecration, and the apparition during the Battle of Parabiago.