Old Italian embraced by Petrus Canisius (8)
I believe the answer is:
etruscan
'old italian' is the definition.
(I've seen this in another clue)
'embraced by petrus canisius' is the wordplay.
'embraced by' indicates a hidden word (surrounding letters embrace the answer).
'ETRUSCAN' can be found hidden inside 'petrus canisius'.
(Other definitions for etruscan that I've seen before include "Early Roman" , "Centaurs (anag) -- native of an ancient state of central Italy" , "Old Italian language" , "Northern Italy" , "Ancient Italian language" .)