Architect I.M. Pei has designed some of the world’s most celebrated buildings over the course of his lengthy career, from Le Grand Louvre in Paris to the Bank of China in Hong Kong. But while Pei is known for his large-scale projects, he also took on some smaller structures, including one that doesn’t get mentioned in biographies or résumés: a barn in Garrison, New York.

What prompted the future Pritzker Prize winner to renovate a barn more than a century old? According to William Pugh of Houlihan Lawrence, who is handling the sale of the $2.495 million, six-acre property, it was friendship. The property’s owner at the time, Dr. Ed Loman, would come up to Garrison from New York City; when he became interested in creating a weekend retreat, he turned to his friend Pei. They completed the project during the summers of 1954 and 1955, transforming the time-worn barn into a modern masterpiece.

The center section of the barn was turned into the main family room and a yellow spiral staircase leads up to the former hayloft, which is now home to three bedrooms and a bathroom. The north wing of the barn became a kitchen and the south wing a den.The front of the structure is unadorned, with a single window and door, but the rear and sides of the building are lined with floor-to-ceiling windows and sliding glass doors connecting the interior with the natural landscape. “They moved the barn from the north side of the property to the south side,” says Pugh. “The location, the flow of the gardens, and the back deck down to the pool were all things influenced by Pei.”

The front of the structure is unadorned, with a single window and door, but the rear and sides of the building are lined with floor-to-ceiling windows and sliding glass doors connecting the interior with the natural landscape. “They moved the barn from the north side of the property to the south side,” says Pugh. “The location, the flow of the gardens, and the back deck down to the pool were all things influenced by Pei.”

Loman owned the property (which has three other structures, including an 1890s greenhouse) into the 1960s. Since then a pool, a guest house, and a tennis court have been added, but Pei’s barn remains well preserved. The architectural gem is ready to be passed into new hands—with luck, ones that will keep this little-known work by a legendary architect in good condition for years to come.