The palace was built for entrepreneur Ermengildo Castiglioni, who chose architect Giuseppe Sommaruga because of his anticonventional solutions. Castiglioni wanted the palace to reflect his wealth and grandeur; the choice of the Liberty style, a new and "trendy" style, for a building that would be located in the historic centre of Milan, was intended by Castiglioni and Sommaruga as a sort of challenge to the Milanese conservative élite. The most provocative element of the original design turned out to be a couple of nude female statues, by Ernesto Bazzaro, decorating the facade; these raised such turmoil that the local newspaper Guerin Meschino published a series of satyrical illustrations on them, and the Milanese population renamed the palace "Cà di ciapp". The statues, that were intended to represent "Peace" and "Industry", were eventually removed and are now used as decorations of another Milanese palace also by Sommaruga, Villa Faccanoni. The furniture was destroyed by the US army that occupied it in 1945-46 and used it as wood for heating. Only decorations, facades, iron work and lamps were saved. The building was put under the protection of the Beaux Arts on March 5, 1957. In 1967 the Castiglioni family sold the building to the Union of Commerce because of high costs of maintenance and a tax to finance the construction of the subway. Arch. Eugenio Gerli e Ing. Giorgio Keffer signed the project to transform it in an office building. They kept the entrance, the staircase, some large rooms on the first floor, the facades and the house on via Marina. The remaining part was emptied, an auditorium wss built under the garden, a new building was built next to the house on via Marina. The Art Nuoveau expert Rossana Bossaglia opposed the project and asked to use the building as Art Nouveau Museum. The superintendent approved the project because the Trader's Union of menaced to let the building deteriorate. In the 150th anniversary of the birth and the 100th anniversary of the death of Arch. Sommaruga Confcomercio has organized a convention in the building on October 20, 2017 with an exhibit of pictures of the Castiglioni family and has opened it to free guided tours on October 21and 22 ottobre from 10 am to 6 pm.
