Answer
Piet de Jong was a Dutch politician who served as Prime Minister of the Netherlands from 1967 to 1971. He was a member of the Catholic People's Party (KVP). The KVP was a Christian democratic political party that was founded in 1945. It was the largest party in the Netherlands from 1945 to 1977. The KVP merged with the Christian Democratic Appeal (CDA) in 1980.