Question: In which year, was this English rock band formed in Hertford that the lead vocalist Ian Gillan of Sabbath is best known for collaborating with?
Sentence (from "Born Again (Black Sabbath album)"): It was also the last Black Sabbath album for nine years to feature original bassist Geezer Butler, and drummer Bill Ward, until he played the studio tracks on their 1998 live album "Reunion".
Relevant evidence: No