Conversation so far:
What is the name of Karlheinz Stockhausen's wife ?
Doris Andreae (m. 1951; div. 1965) and Mary Bauermeister (m. 1967; div. 1972)

Question: When was he married to Doris Andreae ?
Self-contained rewrite: When was Karlheinz Stockhausen married to Doris Andreae ?