This is the summary of the life that I could find about Sirimavo Ratwatte Dias Bandaranaike. In 1940, she married S.W.R.D. Bandaranaike, who was prime minister of Ceylon (now Sri Lanka). Her husband was assassinated in 1959, so his party called the Sri Lanka Freedom Party (SLFP) chose Sirimavo to be their leader.
In 1960, SLFP won the election, and Sirimavo became prime minister. Her program was the same one that her husband used. She kept the Sinhalese language and culture along with the Buddhist religion, had a socialist economic police, and kept neutrality when dealing with foreign relations. While prime minister, she established Simhaleses as the only official language.
However, in 1965, she had lost popularity, and did not win the election. Nonetheless, she was prime minister again in 1970. This time she further restricted free enterprise, carried out reforming land, nationalized industries, and created a new constitution that made an executive presidency and turned Ceylon into the republic Sri Lanka.
Again, in 1977, she lost popularity and lost the election, SLFP winning only eight of 168 National Assembly seats. In 1980, she was barred from political office and stripped of her rights.
In 1986, President Jayawardene gave her her rights back and she lost the election in 1988 again. In 1989, she joined and became the leader of her adversarial party. In August 1994, her daughter, Chandrika, won the election and appointed Sirimavo prime minister once again, and they governed against Tamil separists.
Just recently, I heard from somewhere that Sirimavo Ratwatte Dias Bandaranaike passed away.
