He was 92.

Cassini died in Long Island, New York, said Senada Ivackovic of Oleg Cassini Inc. The cause of death was not immediately known.

Kennedy, only 31 years old when her husband was elected president, was the pinnacle of style in the White House years from 1961 to 1963. Her simple, geometric dresses in sumptuous fabrics, her pillbox hats and her elegant coiffure were copied by women from ages 18 to 80.

Cassini said that shortly after John Kennedy was elected, he persuaded Jacqueline Kennedy to use him as the creator of her total look, rather than as one of many designers.

The one-time Hollywood costume designer turned couturier had been friendly with the Kennedys for years.