Reagan + Gorbachev
Who were they?
Ronald Reagan was President of the United States from 1981 - 1989. Mikhail Gorbachev was Premier / General Secretary / President of the Soviet Union from 1985 - 1991. At the beginning of Reagan's first term, he called for a massive increase in arms against the Soviet Union (this taking place while Leonid Brezhnev was still the leader of the USSR). When Gorbachev took office, he began to call for the policies of Glasnost and Perestroika, both of which were Soviet political reforms associated with more openness and democracy in political, economic, and social systems. In response, Reagan softened his stance against the USSR. Reagan and Gorbachev would go on to ease (and ultimately remove) tensions between the US and the USSR through a series of treaties. Ultimately, their friendship and cooperation would bring about the end of the Cold War and the Soviet Union.
Why are they important?
During the years that the two held leadership of their respective nations, the tense conflict that had raged for forty years would come to a close. Through a series of Soviet political reforms (such as Glasnost and Perestroika) and treaties (such as the Intermediate-Range Nuclear Forces Treaty), cooperation between the two nations would increase, as would their trade. In the end, the work of Reagan and Gorbachev was crucial to not only ending the Cold War, but also shifting the United States's foreign policy from a unilateral one against the USSR to a multilateral policy focused on nearly the entire world (that continues today).