Aman Rosa Alpina, San Cassiano, Italy

From left: Art hanging inside Aman Rosa Alpina; the hotel's pool terrace. Andrea Wyner/Travel + Leisure

Ever since the Rosa Alpina opened nearly a century ago, it has been synonymous with the legendary hospitality of the family who owns it, the Pizzininis. So it came as a surprise when the beloved retreat, once a village parish house, announced a partnership with the luxury brand Aman . Following a down-to-the-studs renovation, the 51-room hotel mastered a complex contradiction: a cozy Alpine heritage living on through a grand, contemporary lens. The vision of acclaimed designer Jean-Michel Gathy is beautifully rendered in Il Salotto, the sleek lobby bar, with its regional touches like wool wall hangings, soaring floor-to-ceiling windows, and five fireplaces. While there are now four restaurants, a 65-foot outdoor infinity pool, and an 18,000-square-foot spa equipped with a hydrotherapy circuit, some things never change.…