Two veterans of the Swiss luxury watchmaking industry, Henri Stern and Jacques-Louis Audemars, have died.

Stern, former longtime president of Patek Philippe who developed its U.S. market and international network, died Sept. 21 in Geneva, Switzerland. He was 91.

In 1937, the company sent him to New York City to develop U.S. distribution. He established The Henri Stern Watch Agency—Patek Philippe’s first foreign distributor and still the brand’s American distributor—and built up the brand’s U.S. business. In 1958, he returned to Geneva, the company headquarters, to become president and managing director, overseeing the luxury watch brand’s worldwide growth. That same year, he also became sole owner of the family company.

Audemars, longtime chairman of Audemars Piguet and grandson of its co-founder, died Oct. 6 in Geneva, Switzerland. He was 91.

Audemars entered the business in 1933. His posts over the next 43 years included watchmaker, production manager, human resources manager, assistant director, and then director of the brand’s technical and manufacturing department.

He served on the company’s board of directors for 45 years, 26 as president. He was named honorary president in 1992. Audemars also headed the Audemars Piguet Foundation from 1992 until 2000.