Margaret Hilda Thatcher was a British stateswoman and Conservative politician who was Prime Minister of the United Kingdom from 1979 to 1990 and Leader of the Conservative Party from 1975 to 1990. She is well known for her crucial role in the peaceful end of the Cold War in Europe. In 1982, she liberated the Falkland Islands from the Argentine invasion spearheaded by the murderous dictator Leopoldo Galiteri. She also balanced a tough line on communism with skillful personal diplomacy with President Reagan and Soviet leader Michael Gorbachev.