The legacy of the late Rev. Sun Myung Moon will forever be tied to the fight to defeat communism, a cause to which he devoted much of his life’s work and, in the process, earned a place in history as a contributor to the end of the Cold War.

The fall of the Soviet Union was to Rev. Moon, who passed away early Monday in South Korea, much more than a changing of the guard in international politics. To him, it represented a landmark victory in a struggle between good and evil.

“Finally, in 1989, the Berlin Wall was torn down and on Christmas Eve 1991, the Soviet empire collapsed after having held the world in fear for 74 years. I thank God that the free world prevailed in this historic struggle, which truly was an ideological battle over acknowledging God or not,” he said in 2002, speaking at a banquet celebrating the 20th anniversary of The Washington Times, which he founded.

“It is the principle that God works his will on Earth through human beings. I do not have the slightest doubt that God used The Washington Times to help bring an end to the most pernicious worldwide dictatorship in history and gave freedom to tens of millions of people,” he said.

But Rev. Moon’s efforts went far beyond decrying the Soviet Union and its communist ideology. While he never wavered in his vehement opposition to communism’s disregard for religion, Rev. Moon met with communist leaders such as Mikhail Gorbachev in an attempt to build relationships with people with whom he disagreed.

His approach “sought peace and reconciliation and was respectful of the many accomplishments of the Soviet Union,” author Thomas J. Ward wrote in a 2008 essay. Mr. Ward also penned the book “March to Moscow: The Role of the Reverend Sun Myung Moon in the Collapse of Communism.”

“Rev. Moon’s constructive outreach to the communist world bore fruit in 1990 when he met with Soviet leader Mikhail Gorbachev and began to develop projects in collaboration with the Soviet government,” Mr. Ward wrote. “This included bringing hundreds of legislators to the United States to dialogue with their political peers. … It also brought thousands of Soviet young people to the United States to learn about American culture and its underpinnings.”

During his trip to the Soviet Union, he told the Moscow News that his ultimate goal was to end tensions dividing humanity by promoting “dialogue between Muslims and Jews, between blacks and whites in South Africa and between Marxists and Christians,” The Washington Times reported at the time.

Government leaders who stood firm against the Soviet empire recognized the contributions made by Rev. Moon.

As president, Ronald Reagan often praised Rev. Moon’s work and that of The Times, which, especially in the 1980s, focused extensively on communism and its attempted expansion around the globe.

Reagan’s counterpart in the United Kingdom, Prime Minister Margaret Thatcher, also has extolled Rev. Moon’s efforts to speed the collapse of the Soviet Union.

“It was not easy for Dr. Moon when he started The Washington Times,” she said in 2007 as the paper celebrated its 25th anniversary. “I mean the firm standing of the newspaper against Soviet communism and the support he gave to President Reagan and me for ending the Cold War.”

In 1991, Rev. Moon returned to North Korea, the land of his birthplace before the division of Korea, for a meeting with the nation’s communist leader, Kim Il-sung.

The fact that the North Korean government had imprisoned Rev. Moon for disturbing society in 1948 didn’t dissuade his return, and North Korea’s state media reported that the two men exchanged “warm conversation overflowing with the love of compatriots.”

Rev. Moon used the opportunity to express his unwavering desire to see the Korean Peninsula reunited.

“I am ready to lay down my life for national reunification,” he said during the trip, according to accounts by The Times.

Mr. Kim also recognized the growing influence Rev. Moon wielded in the U.S.

During the meeting, Mr. Kim asked Rev. Moon to arrange a meeting with President George H.W. Bush, though the desired meeting never took place.