EWTN Catholic Q&A
Power of Pope immediate?
Question from Susan Bennett on 04-19-2005:

Does the Pope take power immediately upon election? I believe he does, but I was asked. Also, is there a Mass to celebrate his election?

Answer by Colin B. Donovan, STL on 04-26-2005:

His authority is immediate. On Sunday he was installed with the symbols of that authority, the pallium, symbol of a bishop who superintends other bishops (a metropolitan), and the fisherman's ring, proper to the bishop of Rome.