The college or body of bishops has no authority unless united with the Roman Pontiff, Peter's successor, as its head (CCC 883). This collegial nature is expressed in a particular way in an ecumenical council (CCC 884).
Successors of the Apostles
Just as St. Peter and the other apostles constituted a single apostolic college, so in like fashion the Roman Pontiff and the bishops are joined together (CCC 880).
Frequently Asked Questions
Does collegiality diminish the Pope's power? No, for the Pope is the head of the college and his supreme authority is not diminished by the collegial action of the bishops (CCC 883).
May the Lord bless you and keep you.