Complex sentence: In 1965 he formed the Jimmy Cotton Blues Quartet, with Otis Spann on piano, to record between gigs with Waters's band and eventually left Waters to form his own full-time touring group.
Split into simpler sentences: In 1965 he formed the Jimmy Cotton Blues Quartet, with Otis Spann on piano, to record between gigs with Waters's band. He eventually left Waters to form his own full-time touring group.