The Aurora Hall stands as the apex of an intricate iconographic system that wisely blends the themes of Greek mythology with that of Jewish-biblical culture and the political-social system of the 17th century. The fulcrum of the room’s decoration is a fresco of a medallion, depicting the Apparition of the Sun Chariot at Dawn, attributed to Giovanni Stefano Doneda so-called Montalto (1608-1690).
In the painting,the glory of the noble house and the ideology of the state are one: in the difficult historical period after the peace of the Pyrenees in 1659, the Arese family had the courage to assume that the Spanish monarchy would not decline, as a great part of Europe would have desired, but that it would have had a radiant future, as can easily be gathered in the renewed hope given by the birth of Carlo II (1661) who, after a long series of deaths among the royal progeny, had overcome the risk of the extinction of Spain’s Hapsburg lineage.
The central medallion is inserted in a golden decoration and blue cornice against a white background of 18th century origin, attributable to Mattia Bortoloni (1695-1750) and achieved, probably to celebrate the wedding of Renato III Arese Borromeo and Marianna Erba Odescalchi, in 1743. The decorative layout, proceeding from the north-east corner going clockwise, comprises furthermore a cycle of sails alternated with smaller painted lunettes, wherein the classical theme of the iconography of dancing satyrs is combined with portrayals of the loves of the mythological divinities. The sequence of the sails, not all preserved up to our time, once included: “Apollo and Daphne,” “Bacchus and Arianna” (scene almost lost), and the portrayal of “Erotes and the Goat Amalthea.” The series of lunettes, instead was composed of the “Triumph of Arianna” (scene now lost), “Diana and Acteone,” “Orpheus and ed Eurydice,” “Venus and Adonis,” “Arianna and an erotes”, “Triumph of Galatea,”, “Arion, Jupiter and Calixtus,” “Pan and Syrinx surprised by Apollo” and the “Divinization of Arianna.”
Before the appearance of these 18th century decorations there were eight paintings on the walls, depicting full figures of Spanish sovereigns and the space of the lunettes were filled with twelve octagonal paintings with the portraits of princes, which was why the hall was called “Grand Hall of portraits.”