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Becoming Catholic #40—Papal Snapshot: Pagan Historian Acknowledges “the higher authority of the bishop of the Eternal City” (c. 355)

The “Becoming Catholic” series presents the biblical, philosophical, and historical evidence for why Eternal Christendom Founder, Joshua Charles, became and remains Catholic. The series table of contents is here.

MATTHEW 16:18-19

“And I tell you, you are Peter, and on this rock I will build my church, and the gates of Hell shall not prevail against it. I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.”

LUKE 22:31-32

“Simon, Simon, behold, Satan demanded to have you, that he might sift you like wheat, but I have prayed for you that your faith may not fail; and when you have turned again, strengthen your brethren.”

JOHN 1:42

Jesus looked at him, and said, “So you are Simon the son of John? You shall be called Cephas” (which means Peter).

JOHN 21:15-17

When they had finished breakfast, Jesus said to Simon Peter, “Simon, son of John, do you love me more than these?” He said to him, “Yes, Lord; you know that I love you.” He said to him, “Feed my lambs.” A second time he said to him, “Simon, son of John, do you love me?” He said to him, “Yes, Lord; you know that I love you.” He said to him, “Tend my sheep.” He said to him the third time, “Simon, son of John, do you love me?” Peter was grieved because he said to him the third time, “Do you love me?” And he said to him, “Lord, you know everything; you know that I love you.” Jesus said to him, “Feed my sheep.”

ACTS 15:7

Peter rose and said to them, “Brethren, you know that in the early days God made choice among you, that by my mouth the Gentiles should hear the word of the gospel and believe.”

This is the first installment of a type of article we are calling “Papal Snapshots.” Each one will highlight a brief example, story, and/or quote that either makes the case for, or refutes an objection to, the papacy.


St. Athanasius (c. 296/98-373) and Emperor Constantius (317-361)

This “Papal Snapshot” concerns the acknowledgment of “the higher authority of the bishop of the Eternal City” by the pagan historian, Ammianus Marcellinus, relating to an event that took place in 355.

Our Roadmap is as follows:

  • Our thesis is that this account provides good evidence that in the mid 4th century, the superior authority of the Pope was known not only to pagan historians, but Arian-friendly Roman emperors such as Constantius (who is mentioned by Ammianus). We will show this by:
  • Providing historical context for the events described; then
  • Quoting the account of Ammianus Marcellinus; then
  • Summarizing the conclusions we believe can be reasonably inferred from this account.

Historical Context

In the aftermath of the Council of Nicaea in 325, the doctrinal division between Catholics and the Arians continued to divide the Roman world. One of the greatest champions of the Nicene definition that affirmed the divinity of Christ was St. Athanasius of Alexandria. He was a constant target of Arian plots, and was exiled from his diocese at least five times.

By the time of the event recorded by Ammianus Marcellinus, St. Athanasius had been condemned by several eastern councils of bishops, including the Synod of Tyre in 335, and the Synod of Antioch in 341. The synod being referenced here is the Synod of Milan in 355, which was originally intended to be a general council like Nicaea, as Emperor Constantius—who was emperor of the entire empire, not just the west—desired to obtain doctrinal uniformity throughout the empire. After the synod, which was co-opted by Arians and condemned St. Athanasius, Constantius asked Pope Liberius to approve of the sentence against him. He refused, and in response the emperor banished him from Rome. The Church historian Sozomen also mentions the incident.1 St. Athanasius also discusses this and other incidents related to the persecution of Pope Liberius, and observed: “these impious men [the Arians] reasoned thus with themselves: ‘If we can persuade Liberius, we shall soon prevail over all.’”2

The Account of Ammianus Marcellinus

Ammianus Marcellinus (c. 330-c. 390-400) was a pagan Roman historian of the 4th century. His work, Res gestae (“Things Done”), provides an interesting anecdote on the aforementioned historical events that sheds light on papal authority (Book 15, Ch. 7)3:

During Leontius’s administration [as prefect of Rome] Liberius [the Pope] the Christian bishop was summoned to appear before the imperial tribunal; his offense was resistance to the orders of the emperor and the decision of a majority of his brother bishops in a matter on which I will briefly touch. Athanasius, then bishop of Alexandria, who was persistently rumored to have thoughts above his station and to be prying into matters outside his province, had been deposed from his office by an assembly of the adherents of the same faith, meeting as what they call a synod. It was alleged that, being deeply versed in the interpretation of oracular sayings and of the flight of birds, he had on several occasions foretold the future events; he was also charged with other practices inconsistent with the principles of the faith of which he was a guardian. Liberius shared the views of his brethren, but when he was ordered by the emperor to sign the decree removing Athanasius from his priestly office he obstinately refused; he declared that it was entirely wrong to condemn a man unseen and unheard, and openly defied the emperor’s wishes. Constantius, who was always hostile to Athanasius, knew that the sentence had been carried out, but was extremely eager to have it confirmed by the higher authority of the bishop of the Eternal City. Failing in this object, he just managed to have Liberius deported under cover of night. This was a matter of great difficulty because of the strong affection in which he was held by the public at large.


From this anecdote, we can discern three facts relevant to papal authority:

  • First, Ammianus, a pagan, was aware of the superior authority of the Pope, and reports it without any need to explain it.
  • Second, Emperor Constantius, an ally of the Arians, was also aware of the superior authority of the Pope. Hence his attempt to co-opt Pope Liberius for Arian purposes.
  • Finally, Ammianus’s reference to “the higher authority of the bishop of the Eternal City” means that both he and Constantius believed (or at least knew many Christians believed) that papal authority was superior to that of at least a synod of bishops, which in this case included—and was eventually co-opted by—bishops from the east. Constantius’s behavior subsequent to Liberius’s refusal to condemn St. Athanasius seems to confirm this.


  1. Sozomen, Ecclesiastical History (Book 4, Ch. 11) (c. 440). ↩︎
  2. St. Athanasius, History of the Arians (Part 5, §35) (358). ↩︎
  3. Ammianus Marcellinus, Walter Hamilton, trans., The Later Roman Empire (AD 354-378) (New York: Penguin Books, 1986), 80. ↩︎
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