Conversation so far:
What kind of sweaters did The Clancy Brothers make famous?
Aran sweaters.
What was their first popular song?
Brennan on the Moor", "Jug of Punch", "Reilly's Daughter", "Finnegan's Wake", "Haul Away Joe", "Roddy McCorley", "Portlairge" and "The Moonshiner".

Question: What brought about their success?
Self-contained rewrite: What brought about The Clancy Brothers' success?