 On 9 June 1604 he also received the title of cardinal by Pope Clement VIII, being given the titulus of San Cesareo in Palatio.In his rule of the diocese, Madruzzo fought heresy and the (often alleged) presence of witchcraft in Trentino, as well as in enforcing the dispositions of the Council of Trent.As a temporal prince, he also strove to find a balance of power with the nearby Habsburg preponderant presence.