Conversation so far:
What group of Frank Zappa's disbanded?
Frank Zappa and the Mothers of Invention disbanded in 1969.
When did The Mothers of Invention disband?
Frank Zappa and the Mothers of Invention disbanded in 1969.
What kind of music did The Mothers of Invention play?
Their sound mixed R&B, doo-wop, musique concrète, and experimental sound collages that captured the freak subculture of Los Angeles at that time.

Question: Why did they break up?
Self-contained rewrite: Why did The Mothers of Invention break up?