Shultz served as secretary of state for six years under former President Ronald Reagan and is credited with steering a peaceful U.S. foreign policy at the close of the Cold War. In addition to secretary of state, Shultz served as treasury secretary, director of management and budget, and labor secretary under former President Richard Nixon.

“He was a true Marine by countenance, determination & strength. An American patriot always,” former Secretary of State Mike Pompeo said in a tweet.

Former Florida Governor Jeb Bush described Shultz as a “patriot, visionary, brilliant, statesman and role model for many.”

Shultz pioneered the nuclear disarmament between Reagan and Soviet leader Mikhail Gorbachev, despite opposition from the Pentagon and other government officials.

“I don’t think it’s possible to overestimate the role that Shultz had on the American political scene and causing the world to think about the danger of nuclear weapons and leading the charge to abolish nuclear weapons,” said former Defense Secretary William Perry on Sunday.

Shultz was confirmed 97-0 for secretary of state, a role assumed in 1982. He held multiple meetings with Gorbachev which resulted in a reduction of nuclear weapons and the Soviet Union pulling out from Afghanistan.

“We have lost a champion of diplomacy, an advocate of American leadership, and a model of public service,” tweeted former Secretary of State Madeleine Albright.

Reagan awarded Shultz the Presidential Medal of Freedom in the last speech of his presidency.

“He believed in diplomacy, but never forgot that successful diplomacy took sustained effort, what he compared to gardening, if flowers were to win out over weeds,” said Richard Haass, president of the Council on Foreign Relations.

Shultz was born in New York City in 1920 and grew up in Englewood, New Jersey. He graduated from Princeton University in 1952 and then joined the Marines to serve in the Pacific. He earned a doctorate in industrial economics from the Massachusetts Institute of Technology after World War II.

“Had the honor of meeting with him a number of times & always walked away smarter and feeling better about our country and our future,” tweeted former New Jersey Governor Chris Christie.

Shultz was the Thomas W. and Susan B. Ford Distinguished Fellow at the Hoover Institution and professor emeritus at Stanford’s Graduate School of Business.

“Our colleague was a great American statesman and a true patriot in every sense of the word. He will be remembered in history as a man who made the world a better place,” said Condolezza Rice, former secretary of state and current director of the Hoover Institute, in a statement.

Former New York City Mayor Mike Bloomberg wrote in a tweet that Shultz was a “giant on the world stage” and his work “touched all facets of American life.”

Shultz, who died at his home in California, was remembered by San Francisco Mayor London Breed: “He was a fierce advocate for what many of us consider ‘San Francisco values,’ including the value of mutual respect and dignity for people from all walks of life.”

Under the Nixon administration, Shultz spearheaded the integration of schools in the Deep South, The New York Times reported. He also led the “Philadelphia Plan” as secretary of labor under Nixon, which prevented trade unions from remaining all white by requiring government contractors bidding on federal construction contracts to hire a number of non-white workers.

Wendy Sherman, director of the Center for Public Leadership at the Harvard Kennedy School, said that Shultz “taught us to ’tend the garden’ of relationships so we could face crisis together when it came.”

Shultz is survived by his wife, Charlotte Mailliard Shultz, and his five children—Margaret Ann Tilsworth, Kathleen Pratt Shultz Jorgensen, Peter Milton Shultz, Barbara Lennox Shultz White, and Alexander George Shultz—as well as 11 grandchildren and nine great-grandchildren.