WASHINGTON (AP) — President Ronald Reagan’s longtime secretary of state, George P. Shultz, has died at age 100.

Shultz spent most of the 1980s trying to improve relations with the Soviet Union and forging a course for peace in the Middle East.

Shultz died Saturday, according to the Hoover Institution, a think tank on the Stanford University campus where he was a distinguished fellow.

Shultz held three major Cabinet posts in Republican administrations during a long career of public service.

He was labor secretary and treasury secretary under President Richard Nixon before spending more than six years as Reagan’s secretary of state.

He had been the oldest surviving former Cabinet member of any administration.