November 19, 1479: a dynastic alliance, two noble scions, a regal wedding, short-lived and with an unhappy ending. These pages reconstruct the story of the magnificent bas relief in the Acton Collection (Villa La Pietra, Florence), commissioned to celebrate the marriage between Antonio Basso Della Rovere, nephew of Pope Sixtus IV, and Caterina Marzano d'Aragona, the niece of King Ferdinand I of Naples. The heraldic symbols of the three coats of arms leave no doubt about the identities of the characters and events surrounding its creation, and lead us to the original location of the work, born as the overdoor to the main portal of the Basso Della Rovere Palace in piazza della Maddalena in Savona. Through close examination of the Della Rovere in Rome, this study highlights some previously unknown facts about the family's origins and returns to Savona and its role as a political, cultural, and artistic protagonist in late 15th-century Italy. AUTHOR: Mauro Mussolin, historian of art and architecture, has published on sacred space and collective rituals, architecture and local identity, religious orders and cities, and architectural models drawings and projects by Michelangelo. 46 colour, 10 b/w images