Taisto Kalevi Sorsa was a Finnish politician who served as Prime Minister of Finland three times: 1972–1975, 1977–1979 and 1982–1987. At the time of his death he still held the record for most days of incumbency as prime minister. He was also a long-time leader of the Social Democratic Party of Finland.

The Social Democratic Party of Finland is a social democratic and pro-European political party in Finland. It is the third largest party in the Parliament of Finland with 43 seats. Founded in 1899 as the Workers' Party of Finland, the SDP is Finland's oldest active political party and has a close relationship with the Central Organisation of Finnish Trade Unions. It is also a member of the Party of European Socialists, Progressive Alliance, Socialist International and SAMAK.