Sirimavo did not begin a career in politics until after her husband was shot dead on 26 September 1959. She was named successor to her husband's leadership of the party. She led that party to win elections in July 1960, promising to continue her husband's policies. Bandaranaike became Prime Minister on 21 July 1960. She was the first female prime minister in the world, and the first woman to be elected head of government.