 Artists responsible for the interior decoration include Giovanni Benedetto Castiglione with "St. James defeats Moors"; Giovanni Bernardo Carbone (GBC) with "St. James opens Coimbra gates to King Ferdinand"; Valerio Castello with "Martyrdom of St. James" and "St. Peter christens St. James", Giovanni Domenico Cappellino with "Preaching of the apostle", Domenico Piola with "Martyrdom of the saint", Giovanni Lorenzo Bertolotti with "Aurelio and Giovanni", Aurelio Lomi with "Daughters of Zebedee introduce Jesus & saints".At the central crossing, the cupola dome has an "Assumption" fresco, considered the masterpiece of Giovanni Andrea Ansaldo, and restored later by Gregorio De Ferrari.Above the door to the center nave is a "Last Supper" by Giulio Cesare Procaccini, flanked by two "Prophets" attributed to either Gioacchino Assereto, Giovanni Andrea Ansaldo or Giulio Benso; on the ceiling, canvases depicting an "Epiphany", "Entry to Jerusalem", and "Prayer in the Garden" by Giovanni Carlone, while the "Resurrection", "Jesus appears to his Mother" and "Coronation of Virgin" were painted by his brother, Giovanni Battista Carlone.