IT'S ALL RELATIVE

In the center of Milan, the city's quintessential design clan shares a centuries-old palazzo renovated by their forebear, the legendary architect Piero Portaluppi.

- CHRISTOPHER GARIS

The interior courtyard of Milan's Casa degli Atellani, the Castellini family compound. The palazzo was renovated in 1919 and after World War II by architect Piero Portaluppi, and most recently by his grandson, architect Piero Castellini Baldissera, who lives in his grandfather's former home on the property. For details, see Resources.

In Castellini Baldissera's private apartment, a living room alcove is lined with mesh-fronted wooden shelves holding a rare collection of antique marble, including some pieces from ancient Rome, and the ceiling is decorated with a working sundial designed by Portaluppi.

The first time I met Piero Castellini Baldissera was at his home in Casa degli Atellani in the center of Milan. Nicolò Castellini Baldissera, his son and my partner, hadn't provided much forewarning about his family palazzo-about its likely connection to Leonardo da Vinci while he was painting the Last Supper at Santa Maria delle Grazie church across the street, or about the attached apartment building filled with members of his extended family, or even about the museum and café run by his cousin in the middle of the compound's courtyard.

When Piero's ancestor Ettore Conti purchased the 15th-century palace in 1919, he enlisted the help of the legendary architect Piero Portaluppi (the husband of Conti's niece Lia Baglia, whom he later adopted) to restore it. He engaged him a second time to repair the complex following damage incurred from shelling during World War II. Portaluppi reimagined the crumbling Renaissance architecture in the neoclassical style while incorporating such 20th-century Milanese references as geometric mosaic floors and an elaborate butterfly window.