Lloyd and Barbara founded Macklowe Gallery in 1966 with $300. During their first visit to Paris, they were enchanted by the mysterious beauty of Art Nouveau and a lifelong passion was born. While their original focus was on art glass and ceramics, Barbara's passion led Macklowe Gallery to become one of the most respected and celebrated sources for rare and collectible jewelry. The Macklowes opened their eponymous gallery in New York City in 1971, and over the years became pre-eminent dealers of French art nouveau furniture, Tiffany lamps and antique and estate jewelry. Ultimately, they turned the business over to their son and retired from gallery life. Mr. Macklowe is the brother of real-estate developer Harry Macklowe, who owns a house across the street in East Hampton. They recently listed their waterfront property in the Hamptons for $60 million. For years, the East Hampton house was the couple’s country home. Mrs. Macklowe said the decision to sell it came down to time and age. She is 80; Mr. Macklowe is 87. In 2019, they sold their apartment on Fifth Avenue in Manhattan for $5.35 million, records show. The couple’s primary residence is in Palm Beach, Fla., where they own a waterfront apartment.