Thatcher was born Margaret Hilda Roberts in Grantham. She married Denis Thatcher in 1951. Thatcher was elected to the House of Commons in 1959. After the Conservative defeat in 1974 she won leadership of the party the following year. In 1979 she led the Conservatives to victory, vowing to reverse Britain’s economic decline and to reduce the role of government. In 1982 Argentine forces occupied the Falkland Islands, which were claimed by both Argentina and the United Kingdom. The British military defeated the Argentine military. She led the Conservatives to further victories in the 1983 and 1987 parliamentary elections, becoming the first British prime minister in the 20th century to serve three consecutive terms.
In 1990, controversy over Thatcher’s tax policy and over her reluctance to commit the United Kingdom to full economic integration with Europe inspired a strong challenge to her leadership. She resigned in November, 1990.