Wikipedia cites a book by E.R. Chamberlin, “The Bad Popes” quoted below.

“The Bad Popes is a 1969 book by E. R. Chamberlin documenting the lives of eight of the most controversial popes (papal years in parentheses):

1. Pope Stephen VI (896–897), who had his predecessor Pope Formosus exhumed, tried, de-fingered, briefly reburied, and thrown in the Tiber.

2. Pope John XII (955–964), who gave land to a mistress, murdered several people, and was killed by a man who caught him in bed with his wife.

3. Pope Benedict IX (1032–1044, 1045, 1047–1048), who “sold” the Papacy.

4. Pope Boniface VIII (1294–1303), who is lampooned in Dante’s Divine Comedy.

5. Pope Urban VI (1378–1389), who complained that he did not hear enough screaming when Cardinals who had conspired against him were tortured.

6. Pope Alexander VI (1492–1503), a Borgia, who was guilty of nepotism and whose unattended corpse swelled until it could barely fit in a coffin.

7. Pope Leo X (1513–1521), a spendthrift member of the Medici family who once spent 1/7 of his predecessors’ reserves on a single ceremony [book: Bad Popes].

Also sold indulgences to build the new Saint Peter’s Basilica; his predecessor had torn down the old one. [source: NCRegister, Kevin Di Camillo, November 26, 2019; How Bad Were “the Bad Popes?”]

8. Pope Clement VII (1523–1534), also a Medici, whose power-politicking with France, Spain, and Germany got Rome sacked.” [#1-8 source: Wikipedia and the book “The Bad Popes”]

9. Pope Vigilius (537-555) – my pick for the worst Pope, only for acts chosen prior to becoming Pope.

10. Pope Sergius III – murdered Benedict IV and Leo V in order to obtain the papacy by force. [source: Dave Armstrong, “Sinful and Reckless: How Many Bad Popes Were There?” Patheos blog]

11. Pope Clement VI (1342-1352) accused of having a mistress and leading a “dissolute” life. [source: Armstrong]

12. Pope Julius III (1550-1555) accused of sex with his nephew; alternately, accused of being the father of the “nephew”. [source: Armstrong]

13. Pope Saint Peter, the Prince of the Apostles, Rock on which the Church is founded – accused by Peter Kwasniewski of being one of the Popes who “Popes Who Connived at Heresy or Were Guilty of Harmful Silence or Ambiguity”. Specifically accused by Kwasniewski of: “he did shamefully compromise on the application of an article of faith, viz., the equality of Jewish and Gentile Christians and the abolition of the Jewish ceremonial law – a lapse for which he was rebuked to his face by St. Paul (cf. Gal 2:11).” Kwasniewski also alleges that our Lord “allowed His first vicar to fail more than once”. [source: “Lessons from Church History: A Brief Review of Papal Lapses”, Peter Kwasniewski August 6, 2018, OnePeterFive.com]

14. Pope Saint John Paul II (1978-2005) – accused by Peter Kwasniewski of sacrilege, blasphemy, religious indifferentism, and “dereliction in his duty” and teaching freedom of religion; others accuse John Paul II of idolatry, all for the same reason, the praying at Assisi with persons of other religions.

15. Pope Saint Paul VI (1963-1978) – accused by Peter Kwasniewski of approving the documents of Vatican II; of teaching the fundamental human right of freedom of religion; approved the Novus Ordo (vernacular) Mass.

Analysis of the above Accusations

1. Pope Stephen VI – There is no heresy or grave teaching errors alleged here; he was pressured by secular authorities to put his predecessor, Pope Formosa on trial after his death. As Roman Pontiff, Formosus had crowned a new emperor, Arnulf. But when Arnulf fell ill, and lost power over Italy, his political enemy, Lambert, pressured the new Pope to condemn Formosus. So the trial was held not because the Pope thought it fitting to put a predecessor on trial, but to avoid the wrath of the new ruler over Italy, who was very angry at the Church for siding with his opponent and making him emperor.

2. Pope John XII – installed as Pope by his powerful family at the age of about 20 years old; never wanted the office; spent his time partying (as we would say today). He is very likely an antipope, as he was not validly elected, and never accepted the office and role of Roman Pontiff.

3. Pope Benedict IX (1032–1044, 1045, 1047–1048) – supposedly in office three times. He is almost certainly an antipope. To hold office three times, he would have had to have been validly elected, validly resigned, be validly elected again, validly resign again, and be validly elected a third time. Then he was removed from office, not by death or resignation, but by secular authority. He purchased the papacy, which is not a valid election, making his papacy invalid.

4. Pope Boniface VIII (1294–1303), who is lampooned in Dante’s Divine Comedy. There is no good reason to call Boniface VIII a bad Pope. This accusation stems mainly from his document, Unam Sanctam, possibly infallible under Papal Infallibility, but certainly infallible by the declaration of Lateran V, which asserts the authority of the Roman Pontiff over “ever human creature”. This is dogma, not a reason to call him bad.

5. Pope Urban VI (1378–1389), “who complained that he did not hear enough screaming when Cardinals who had conspired against him were tortured.” This story is likely false. It sounds very much like a sarcastic remark someone would make who disliked the Pope. Accusations against Popes should not be assumed to be true. For example, we all know of the ridiculous accusation that Pope Francis doesn’t believe in Hell. This has been proven false by many examples from his own teachings. Yet the claim continues to be made.

In addition, personal sins of a Pope are between that Pope and God. It does not affect the papal charisms of indefectibility, never-failing faith, and freedom from grave error in doctrine and discipline.

6. Pope Alexander VI – succeeded in freeing the Church and the papacy from the influence of powerful families of Rome; was well-versed in Sacred Scripture and guided the Church well; is not accused of failures in faith. He had a mistress and had children by her. Other accusations against him are perhaps fictitious or exaggerated. In any case, he repented, with tears, over many days on his literal death bed, and made a good confession, received Communion, and extreme unction. He very likely died in a state of grace. Worst? Don’t make me laugh.

7. Pope Leo X – Spent money lavishly. If this were true, well, some Popes did commit grave sins, but this does not make them bad Popes. And whether or not they were bad persons is for God alone to judge.

Leo X is also accused of using indulgences to raise money for the building of Saint Peter’s Basilica. The selling of indulgences is wrong. However, in this case, Leo X is INNOCENT!!! Donating money to build Saint Peter’s Basilica is a good work in the category of almsgiving to the Church. Indulgences for any type of good work approved by Christ is moral, virtuous, and praiseworthy. So it is not the sale of indulgences to give an indulgence in exchange for a donation to build a church, especially one that will serve the universal Church for centuries to come.

8. Pope Clement VII – was too involved in politics, just like many Catholics on the far right. Not really a reason to call him a bad Pope.

9. Pope Vigilius (537-555) – my pick for the worst Pope, only for acts chosen prior to becoming Pope. Prior to his papacy: he was a deacon who suggested to the emperor and empress a plan to remove the true Pope, and then make Vigilius pope. He offered to teach heresy and put a heretic on the See of Constantinople as part of this plan. This was done, and the true Pope, Silverius, was forcibly removed from office, and sent into exile. Vigilius became an antipope ruling from Rome and teaching heresy. Then the true Pope, Silverius, died.

At the death of Silverius, Vigilius was accepted by the Church as the true Pope, at which point, according to Saint Robert Bellarmine: “From this time neither error nor feigning of error was discovered in Vigilius, but rather, supreme constancy in the faith even to death, as it shall appear. For he received with the pontificate the strength of faith and he was changed from a weak chaff into the most solid rock.”

Vigilius committed sins greater than any other supposedly bad Pope, but there were committed prior to becoming the true Pope. For sins against the Faith are worse than other types of sins. Vigilius conspired against the true Pope, had him forced into exile, was partially responsible for his death as he was the one who made the plan to force Pope Silverius into exile, and taught heresy as an antipope as if from the Chair of Peter, gravely harming the Church. He is the worst Pope, except that these sins were committed before becoming Pope. As Pope, he had the charism of truth and of never-failing faith, never taught grave error, defended the faith under threats of death, suffered exile, died before being able to return to Rome.

10. Pope Sergius III – murdered Benedict IV and Leo V in order to obtain the papacy by force. [source: Dave Armstrong, “Sinful and Reckless: How Many Bad Popes Were There?” Patheos blog] — He could not possibly be a valid Pope, as he obtained the papacy by murdering his two predecessors.

11. Pope Clement VI (1342-1352) accused of having a mistress and leading a “dissolute” life. [source: Armstrong] The personal sins of a Pope are between him and God.

12. Pope Julius III (1550-1555) accused of sex with his nephew; alternately, accused of being the father of the “nephew”. [source: Armstrong] The personal sins of a Pope are between him and God. We must also not assume that every accusation is true. His “nephew” may well have been his son, conceived with a mistress, and that would explain why they would spend time together alone, not for sex, but as father and son.

13. Pope Saint Peter, the Prince of the Apostles, Rock on which the Church is founded – accused by Peter Kwasniewski of being one of the Popes who “Popes Who Connived at Heresy or Were Guilty of Harmful Silence or Ambiguity”. Specifically accused by Kwasniewski of: “he did shamefully compromise on the application of an article of faith, viz., the equality of Jewish and Gentile Christians and the abolition of the Jewish ceremonial law – a lapse for which he was rebuked to his face by St. Paul (cf. Gal 2:11).” Kwasniewski also alleges that our Lord “allowed His first vicar to fail more than once”. [source: “Lessons from Church History: A Brief Review of Papal Lapses”, Peter Kwasniewski August 6, 2018, OnePeterFive.com]

Kwasniewski is one of the worst of the papal accusers; a schismatic and heretic, who is permitted by Steve Skojec, editor of OnePeterFive, to make vicious attacks on the papacy and the Church, including accusing Pope Saints and Saint Peter himself, falsely, of grave failures in faith and grave errors in doctrine and discipline. It is dogma that every Pope has the charism of truth and of never-failing faith. And his error of eating with only Jewish Christians was a personal error (as Tertullian explains), not an error of doctrine or discipline. Peter did not reject the equality of Jewish and Gentile Christians, as proven by his sending of Paul to the Gentiles while Peter went to the Jews. Peter did not reject the abolition of the Old Testament disciplines; rather, he was at the Council in Acts which taught that those disciplines are not binding on Christians (except for a few, continued for a brief time, later taken away entirely, as Florence taught).

You Shall Not Bear False Witness against your neighbor can hardly be broken in a more severe manner than by accusing many different Popes, as well as Pope Saints and Peter himself, falsely of errors contrary to the papal charisms taught as dogma. And what are these other failings Peter K. accuses Saint Peter of? He does not even say! This is a grave accusation against the person chosen by Christ to be the Rock on which the Church is founded, and Peter K. takes a nasty malicious swipe at Saint Peter without saying what these other failings supposedly are. It cannot be his three-fold denial of Christ, which was prior to the start of his pontificate at the Ascension (Pope Pius XII, Mystical Body of Christ, 40). And Peter K. says “allowed his first vicar”, so that implies errors while Pope. To make such a severe accusation without specifics is gravely immoral.

14. Pope Saint John Paul II (1978-2005) – accused by Peter Kwasniewski of sacrilege, blasphemy, religious indifferentism, and “dereliction in his duty” and teaching freedom of religion; others accuse John Paul II of idolatry, all for the same reason, the praying at Assisi with persons of other religions.

15. Pope Saint Paul VI (1963-1978) – accused by Peter Kwasniewski of approving the documents of Vatican II; of teaching the fundamental human right of freedom of religion; approved the Novus Ordo (vernacular) Mass.

Peter K. accuses Pope Saint Peter, Pope Saint John Paul II, and Pope Saint Paul VI of grave errors, contrary to the dogmas of papal charisms. Freedom of religion is a fundamental human right. To accuse Pope Saints of grave error for teaching a human right is a new level of wickedness for the papal accusers. Then the Church has the authority and right to make changes to discipline. The First See is not judged by Peter K., nor anyone else. Accusing a Pope of a grave error for approving the documents of an Ecumenical Council is thoroughly contrary to the dogmas of the Church on papal and Church authority, and on the indefectibility of the Church. Accusing a Pope Saint of grave sin for praying with persons of other religions is a grave sin against Christ, who gave miraculous healings at the requests of the Centurion (a pagan of the Roman religion) and the woman of Canaan (a pagan of a different religion). Which is greater, to give someone a miracle, or to pray with them? If the greater is permitted, then so is the lesser.

Final Points

If a Pope sins gravely against God, that is between him and God. We do not have the role to judge the consciences and lives of others. If a Pope errs in doctrine or discipline in a way that is less than grave, he is not a bad Pope. The faithful can speak contrary to such a lesser error, thereby assisting the Magisterium. Otherwise, Popes are prevented by the grace of God from erring gravely in doctrine or discipline; Popes have the charism of truth and of never-failing faith; they also have supreme teaching authority, are to be judged by no one but God, and their decisions do not admit of appeal. Then subjection to the Roman Pontiff is entirely from the necessity of salvation.

Discussing the possible sins or lesser errors of historical Popes can be instructive, in that it shows us the graces and the limits of those graces in the Popes. But it is sinful to assume all accusations against any Pope are true. Look at the many false accusations against Pope Francis. And it is contrary to Church law (Canon 1404) to judge the First See. It is schismatic to place one’s self above the Popes to decide whether they have erred gravely in doctrine or discipline. It is heretical to accuse any Pope of grave failures of faith, or grave errors in doctrine or discipline.

What will happen to the papal accusers, who gravely harm souls by scandal, commit heresy and schism, bear false witness in some of the worst ways possible, and sin gravely by pride in thinking that the papacy is filled with grave errors. God is their judge. But they will not escape the justice of God.

If you ask me which is the worst Pope, I will say Pope Vigilius, for his words and deeds as an antipope, prior to becoming true Pope. But as true Pope, Vigilius was blameless in his teachings and his faith. And this is a lesson for the faithful. We can trust the grace of God to guard and guide each valid Roman Pontiff. We do not NEED to stand in judgment over each Pope, to protect ourselves from grave errors, as there are none. FAITH is the answer to the alleged problem of Pope Francis.

Ronald L. Conte Jr.