Three former secretaries of state were among the more than 500 mourners who filled Christ Church on Park Avenue yesterday to memorialize the life of Walter Wriston, the former chairman and CEO of Citicorp credited with making the company a pre-eminent international financial institution.

“He had an easy brilliance,” George Shultz, who served as secretary of state under President Reagan, said. He related a vivid memory of Wriston lecturing a roomful of senior government figures on the evils of wage and price controls in the early 1970s, saying, “Walt never flinched.”

“I admired Walt as a leader, and I loved him as a human being,” Henry Kissinger, who served under President Nixon, said. “He was the kind of American – optimistic, humble, caring – who historically has made this country the hope of the world.”

Alexander Haig, who preceded Mr. Shultz under Reagan, recalled Wriston’s associations with General Macarthur, Margaret Thatcher, Golda Meir, Anwar Sadat, Charles de Gaulle, and seven presidents, concluding, “Walter Wriston belonged in the company of those great men and women.”

Wriston was renowned for inventing the certificate of deposit and for developing Citibank subsidiaries in dozens of countries. He was a leading advocate of lending to developing countries and was invited at least twice to become secretary of the treasury.

Mr. Shultz recalled being in the room at an annual economic meeting he sponsored when Wriston told the economist Milton Friedman: “We are not on a gold standard or a dollar standard. We are on an information standard.”

Always a visionary supporter of information technology, Wriston counted among his most important achievements jump-starting the automatic teller machine through a massive investment in computers while he was president and CEO of Citibank in the 1970s.

He was also, according to Mr. Kissinger, acutely sensitive to the value of other technologies.

“He had the only mechanical stump remover in our corner of Connecticut,” Mr. Kissinger said, adding that he had a lot of downed trees on his own property, near Wriston’s tree farm. “He also thought I was somewhat challenged about economics. Every spring he offered to lease it to me, at increasing rates. It was the Tiffany of stump removers.”

Mr. Kissinger added that Wriston’s sentimentality sometimes overrode his business sense: “If I really needed it, I always knew he would give it to me for free.”