from August 2011 Adsum:

In a recent pamphlet written by a Julio Pro, M.D., objections were raised against the sedevacantists. One “proof” given was the supposed apostasy of Pope St. Marcellinus. It was erroneously claimed that this saintly Pope offered worship to false gods and still remained Pope. The following excerpt refutes this historical error:

“The States subject to Rome, watered with the blood of the persecuted, only because the more productive of Christian branches. Tortures tore the bodies of the martyrs, but their souls, firmly embracing the faith, remained invulnerable and invincible. Nevertheless, there were some weak spirits that yielded to threats, and with whom self-love prevailed over religion; and it has even been said that among those weak ones was Marcellinus himself. The falsehood which was circulated on this head was adorned with all the circumstances which might give it an air of probability. It was pretended that the pontiff, perceiving his fault, presented himself as a suppliant before a council of three hundred bishops, assembled at Sinuessa. There, ran the story, the culprit confessed his error, and, weeping, demanded that she should be sentenced to the punishment he had incurred; and the council replied: ’Pronounced sentence on thyself; the chief see cannot be judged but by itself.’ But in this statement every particular is false; it is now ascertained that the accusation is calumnious, and that the pontiff committed no fault. Saint Augustine, speaking of Petilius, author of that fable, says: ‘He calls Marcellinus a sacrilegious wretch; I declare him innocent. It is not necessary for me to weary myself to support my defence by proofs; for Petilius himself supports his accusations by no proof.”

-excerpt from Lives and Times of the Popes by Chevalier Artaud de Montor (1909)