“Mr. Gorbachev, tear down this wall.” These words from President Ronald Reagan were instrumental in prompting the dissolution of the Soviet Union in the late 1980s and early 1990s. Some Americans are old enough to remember seeing President Reagan make this speech, while others have never known a world without a unified Germany. Mikhail Gorbachev was not only the last leader of the Soviet Union, but he also ushered in a new era in Europe. Gorbachev died on Tuesday, August 30. He was 91.

Communist Russia was the result of the Bolshevik Revolution of 1917. Prior to that, Russia was lead by a Czar (or Tsar), Nicholas II. The Romanov family was assassinated, and Vladimir Lenin would eventually emerge as the leader of Russia. A 1922 treaty between Russia, Ukraine, Belarus and Transcaucasia (modern Georgia, Armenia and Azerbaijan) would form the original Soviet Union (Union of Soviet Socialist Republic). Two years later, Lenin would pass away, and Communist dictator Joseph Stalin would come to power – a place in which he would remain until his death in 1953.

Most Americans today only learned about the horrors of living in the Soviet Union from history class. Stalin oversaw the arrests and subsequent executions of kulaks, wealthy peasant landowners, in order to seize their property. He was also in charge during The Great Purge, in which 600,000 Soviets perished at the hands of the government. During the Great Purge, the Ukraine in particular was subject to a famine historically known as the Holodomor, dubbed such because Stalin collected most of the grain harvests in the Texas-sized nation and drove farmers off their private lands. It’s estimated that nearly 4 million Ukrainians starved as a result.

It’s important to understand just how horrific Soviet life was to comprehend Mikhail Gorbachev’s importance in history. After Stalin died, he was replaced by Nikita Khrushchev. Khrushchev is famous for telling America “We will bury you” in reference to the nuclear power of the Soviets. Other leaders would follow, but in 1985, Mikhail Gorbachev became the General Secretary of the Soviet Union.

Gorbachev was unlike other Soviet Communist leaders. While the Soviet Union was born out of collectivism, Gorbachev had studied Herzen and Belinsky, who, although socialists, wrote about the “dignity of the individual.” Gorbachev was committed to a restructuring of the Soviet Union, a more ” democratic, humane” socialism. Gorbachev would be instrumental in the dissolution of the Soviet Union. Even today, according to NBC News, Russians reacted to the death of this leader “frostily.”

Gorbachev met with Reagan multiple times between his ascension to power in 1985 and his resignation in 1991. The unlikely pair were friends in addition to their roles as world leaders. When Reagan died in 2004, Gorbachev attended his funeral. In 1987, Reagan and Gorbachev worked together to create a deal in which intermediate-range missiles were tossed. The INF treaty would restrict the deployment of certain nuclear missiles across the planet.

Gorbachev was unlike his Soviet leader predecessors because he would meet with and negotiate with his Western counterparts, including Great Britain’s Margaret Thatcher. Thatcher famously said of Gorbachev: “We can do business together.” Gorbachev and Reagan worked together on the INF treaty so that the measure did not “kill” Reagan’s “Star Wars” program, something that took skillful negotiation on the part of both leaders.

Reagan would later tell some trusted staffers, “There’s a chemistry between the two of use, we listen to one another.” The pair was able to find common ground, and some of the most historic steps were taken to free the citizens of the Soviet Union.

While the Cold War didn’t officially end until 1991, when George H.W. Bush was in office, Gorbachev is seen as carrying the torch lit by President Reagan in order to offer a more “healthy, prosperous society” for the people of the USSR. Gorbachev knew without a dissolution of the Soviet Union, the economy could not prosper, and his people wouldn’t either.

Gorbachev passed away at a time when, according to NBC, current president Vladimir Putin has “left in tatters” the domestic reform and Western camaraderie Gorbachev worked so hard to achieve. Putin offered “deep condolences” to the family of Gorbachev. In his later years, Gorbachev had said of Putin: “(his) policies (had led to) the militarization of world politics.”