Pope Victor (192), in the beginning, had approved and endorsed "mondanism" (heresy in the 2nd century) but later condemned it. Pope Marcellin (296-303), was an idolater. He entered the temple of Estia and offered a sacrifice to the goddess. You may say that this was a case of weakness, but I respond, the lieutenant of Jesus Christ dies but does not become turncoat or apostate. Pope Liberius (358) agreed with the condemnation of Athanasius and decided to accept Arianism with the intention of bringing about his freedom from exile and be restored to his earlier office. Pope Honorius (625) followed the monothelitism. This was proved by Father Gratry. Pope Gregory 1st (578-590) calls antichrist anyone who receives the title of Ecumenical bishop, however despite all these, Pope Bonifatius (607-608) forced the patricidal Emperor Phoca to bestow him that title. Popes Paschalius 2nd (1088-1099) and Eugene 3rd (1145) approved duels but were forbidden by Popes Julius 2nd (1609) and Pius 4th (1560). Pope Eugene recognized the Synod of the Kingdom and the restoration of the use of the Holy Chalice in the Church of Bohemia. Pope Pius 2nd (1458) put an end to this privilege, and Pope Adrian 2nd (867-872), pronounced civil marriages valid. Pope Pius 7th (1800-1823) would disapprove of them and Pope Sixtus 5th (1585-1590) announced the issuing of the Holy Bible and with the famous Seal approved its reading. Pope Pius 7th disapproved those who read it. Pope Clemens 14th (1769-1774) abolished the Jesuit Order which was allowed by Pope Paul 3rd. Pope Pius 7th restored it.
From the speech of the Papist Archbishop Josip Jurai Srossmaier at the 1st Vatican Synod in 1870.