Located in the northern side of the main courtyard, the vestibule was an antique atrium of the palace reserved for guests’ access and mentioned in all inventories of that time as the first area of the palace. In fact, from this room it was possible to access either the receiving rooms located on the ground floor or the main upper floor, through the monumental staircase which is currently not open to the public.
The hall is characterized by a much simpler rectangular cross-vaulted layout which was probably one of the waiting rooms before entering the lavish reception rooms, main apartments or the original hall of the Nymph.
This room, which directly overlooks the main courtyard, is set up as a small gallery dedicated to the 17th-century portraits of the Arese family, now preserved on the staircase of the Palazzo Borromeo on Isola Madre and replicated here in copies thanks to a specific project of the association “Experience the Palace and Garden Arese Borromeo” that has successfully combined private and public sponsors.
The decorations of the vault do not present any particular frescoes but only elegant rococo décor softened by the emblems of the two branches of the Borromeo Arese and Erba Odescalchi families.
The most significant work is the fireplace made of molera stone brought in from Cesano Maderno in the 1820s by Guido Borromeo Arese, who transported it from his house in Milan. Cut off, therefore, from the iconographical-figurative project of the palace, the fireplace is characterized by a rich central frieze and by the motto “Sol in exilio ignis” (“fire is the sun in exile”) written on the hood. Moreover, it has a rich frontal decoration with the emblem of the Arese family that is flanked by the four cardinal virtues: Prudence, holding a mirror and looking out for his back; Justice, holding a sword and a scale, evidence of fairness in judging and punishing; Fortitude, holding a column, symbol of support for definition; and Temperance, intent in mixing cold and hot water in two jugs. Among the cardinal virtues, Fame also appears, winged and with a double trumpet. Peace, holding an olive branch, is depicted seated on the ground, surrounded by landscapes of nature.
To complete the decorations are the twin caryatids that appear at the ends of the fireplace which also has two seats in mixtilinear stone.