Pope Saint Caius: The Twenty-Eighth Pope, the Ladder of Holy Orders, and the Emperor's Kinsman

The twenty-eighth in a series on the popes.

The most honest sentence ever written about Pope Caius comes from a Benedictine scholar in the Catholic Encyclopedia, and it is a confession of defeat: “Nothing whatever is known of his life.”⁠¹ Here is a man who sat in the chair of Peter for more than twelve years—longer than all but a handful of the popes of the first three centuries—and of whom the historical record preserves, essentially, a name, two dates, and a place of burial. Eusebius, writing within living memory of him, spares him a single clause. The great pope-book of the Middle Ages fills the vacuum with a biography, and nearly every line of that biography dissolves under examination. And yet Caius is not quite the cipher that Felix, his predecessor two removes back, was. Something of his does survive—not a letter, not a decree, but a stone: the broken slab that marked his grave, dug out of the earth of a Roman catacomb fifteen centuries after his death and pieced back together, bearing his name and one plain title. The paradox of Caius is that the age which knew almost nothing about him invented almost everything, while the one solid relic it left behind was the thing it never thought to forge.

This is the twenty-eighth entry in my series on the popes, which has followed the bishops of Rome in order from Peter down to Caius’s immediate predecessor, Eutychian, the twenty-seventh. Caius’s pontificate frames a question the whole series keeps circling—what it meant to lead the Roman church in the last long peace before the worst persecution it would ever face.

The Longest Reign Nobody Remembers

Begin, as always, with what can actually be documented, because with Caius it does not take long. He became bishop of Rome on 17 December 283 and died on 22 April 296—dates supplied not by any contemporary biographer but by the fourth-century Liberian catalogue, which gives his reign as twelve years, four months, and seven days. Even here the sources will not agree. Eusebius allots him “about fifteen years”; the Liber Pontificalis gives eleven years and some months; the Liberian figure, which modern scholarship follows, splits the difference and is probably right.⁠² The disagreement over so basic a fact is itself the signature of Caius: a pope substantial enough to hold the see for over a decade, obscure enough that no one troubled to write down how long.

Eusebius is our earliest witness, and he is almost comically brief. Having closed the reign of Felix, he records the whole succession in a breath: Felix “was succeeded by Eutychianus, but he in less than ten months left the position to Caius, who lived in our day. He held it about fifteen years, and was in turn succeeded by Marcellinus, who was overtaken by the persecution.”⁠³ That is the entire notice—a name, an estimate of years, and two neighbors in the list. But one phrase in it is worth pausing over. Eusebius calls Caius one “who lived in our day,” kath’ hēmas: the historian of the early Church counted this pope a near-contemporary, a man of his own generation. Caius is thus, paradoxically, better placed in real time than the more famous popes of the century before him, and yet Eusebius, who could have asked men who remembered him, found nothing to say. Silence this close to the source is not the silence of ignorance. It is the silence of a reign in which, by the mercy of the times, very little happened.

For the times were merciful, and that is the key to the whole pontificate. Caius reigned entirely within what historians call the Little Peace of the Church—the span of roughly forty years, from about 260 to 303, in which the Roman state left the Christians alone. It had opened when the emperor Gallienus, after the capture of his father Valerian by the Persians, reversed the persecution and, as Eusebius reports, “conducted the government more prudently,” restoring to the bishops the freedom to perform their duties and returning the confiscated cemeteries to the Church.⁠⁴ For the first time Christianity was something like a tolerated religion, holding property, running its charities, ordaining its clergy in the open. Caius became pope twenty-three years into that peace and died seven years before it ended. He never saw a persecution. The great terror that his legend would later attach to his name—the persecution of Diocletian—did not begin until February 303, and Caius had been dead since 296.⁠⁵ The storm gathered offstage, in the reign of an emperor who for two decades left the Christians in peace and then, near the end, turned on them with a ferocity none of his predecessors had matched. But it broke over Caius’s successor, not over Caius. He is the last pope of the calm.

That calm is the true frame for everything the legends dramatize. When the Liber Pontificalis pictures Caius hiding in the catacombs from Diocletian’s soldiers, it is projecting the ordeal of the next generation backward onto a bishop who, in fact, governed a church that was growing, wealthy, organized, and unmolested. The heroism the medieval biographers wanted to give him belonged to the men who came after. What actually belonged to Caius was something less dramatic and, for the historian, more interesting: a long stretch of institutional consolidation, the quiet years in which the Roman church became the machine that the persecutions of the fourth century would fail to break.

The Emperor’s Kinsman

The single most memorable thing the tradition says about Caius is almost certainly false, and it is worth examining precisely because of how the falsehood was made. The Liber Pontificalis opens his life with a striking claim: “Gaius, by nationality a Dalmatian, of the family of Diocletian, the emperor, son of Gaius.”⁠⁶ A pope who was blood kin to Diocletian—the very emperor whose name is a byword for the bloodiest assault the early Church endured. The irony is almost too neat, and neatness, in hagiography, is a warning sign. Diocletian was himself a Dalmatian of obscure origin, born near Salona on the Adriatic coast; the legend simply gave Caius the same homeland and then promoted proximity into kinship. There is no historical basis for the relationship whatever. It is a genealogy of coincidence, manufactured to lend the obscure pope the drama of a family tie to his Church’s greatest persecutor.

The kinship claim did not travel alone. It came bundled with a whole family romance, drawn from one of the more elaborate of the late Roman hagiographical fictions, the Passio of Saint Susanna. In that tale Susanna is a Christian virgin, daughter of the presbyter Gabinius and niece of Pope Caius, who is himself kin to Diocletian; refusing a marriage the emperor’s household presses on her, she is beheaded in her father’s house. The Liber Pontificalis absorbed the story, making Caius a martyr crowned “in company with Gavinius, his brother, on account of the daughter of Gavinius the priest, whose name was Susanna.”⁠⁷ The trouble is that the Passio Susannae is a late composition—scholars date it to roughly 450 to 500, a century and a half after Caius—and it is, in the judgment of its most recent editor, a work of no historical value, its family relationships a hagiographer’s invention.⁠⁸ A real martyr named Susanna may lie somewhere beneath the cult, but the biography that names her uncle a pope is invention.

Why invent it? Here the legend becomes genuinely illuminating, because it was built to explain something real: a church. On the Quirinal hill, hard by the Baths of Diocletian, stood one of the oldest of the Roman title-churches—the parish churches whose names anchored the city’s Christian topography. In the fourth-century records it is called the titulus Gaii, the “title of Gaius,” or, from the two houses that formed it, the church ad duas domos, “at the two houses.” By the end of the sixth century it had acquired a new name and become the church of Santa Susanna, which it remains.⁠⁹ A title-church named for a “Gaius,” standing beside Diocletian’s own baths: that was the raw material. The hagiographer took the church’s name, the emperor’s neighboring monument, and a martyr called Susanna, and wove them into a single story—Susanna the niece, Gaius the uncle-pope, Diocletian the imperial persecutor next door. As it happens, the older sources do not even agree that the Gaius of the title was the pope; the Catholic Encyclopedia, following one recension of the legend, calls him “the prefect Caius.”⁠¹⁰ The identification of the church’s Gaius with Pope Caius may itself be a coincidence of names, seized on and elaborated. The whole gorgeous legend is a story invented to give a face to a place.

The Ladder to the Altar

If the kinship legend is the tradition’s most memorable claim about Caius, its most consequential is the decree on holy orders—and it repays a closer look, because here the fabrication conceals a genuine truth. The Liber Pontificalis credits Caius with regularizing the whole path to the episcopate. In its fuller form the decree reads that “whoever was worthy to be bishop must first be doorkeeper, reader, exorcist, acolyte, subdeacon, deacon, priest and then be ordained bishop.”⁠¹¹ Here, laid out in a single sentence, is the ladder of the clergy that the Latin Church would climb for the next seventeen centuries: the four minor orders—porter, or ostiarius; reader, or lector; exorcist; and acolyte—followed by the three higher grades of subdeacon, deacon, and priest, and crowned by the fullness of the episcopate. No one, the decree insists, vaults to the top; the bishop is a man who has stood at every rung.

It is a tidy origin story, and it is not true—at least not as an origin. The graded Roman clergy did not begin with Caius, because it was already fully in place a full generation before him. The proof is a document this series has had occasion to quote before: the letter Pope Cornelius wrote around the year 251, some thirty years before Caius took office, in which, to shame the schismatic Novatian, he rattled off a census of the Roman church. It counted, Cornelius says, “forty-six presbyters, seven deacons, seven sub-deacons, forty-two acolyths, fifty-two exorcists, readers, and janitors, and over fifteen hundred widows and persons in distress.”⁠¹² Every grade the Liber Pontificalis would later credit Caius with instituting is already there in Cornelius’s letter—subdeacons, acolytes, exorcists, readers, doorkeepers, the whole ordered hierarchy beneath the deacons and presbyters—counted out like the payroll it in effect was. The translator of the pope-book herself flagged the anachronism in a footnote, pointing to Cornelius as “the earliest known enumeration of the seven ranks in the hierarchy of the order.”⁠¹³ What the medieval biographer imagined as a papal decree, the mid-third-century evidence shows as an already-living institution.

The orders had come into being not by fiat but by slow accretion across the second and third centuries—the reader is attested already in Tertullian around the year 200, the subdeacons and acolytes and exorcists first named as distinct offices in Cornelius’s letter of 251—so that by Caius’s day the Roman church possessed a professional clergy of more than a hundred and fifty men arranged in seven grades beneath a single bishop.⁠¹⁴ The Liber Pontificalis was not wrong that Rome had a ladder of orders. It was only wrong about who built it. Crediting the structure to a specific pope was the pope-book’s characteristic move: it liked to give every custom a founder, and Caius, obscure and long-reigning, was a convenient name to hang the whole apparatus on.

And yet the underlying instinct was sound, for the ladder points at something the Church has always held to be of the essence. The minor orders were never themselves the sacrament of Holy Orders; they were preparatory offices, stages of formation and service on the way to the altar. The sacrament proper has, from the beginning, three degrees and only three. As the Catechism puts it, Holy Orders “includes three degrees: episcopate, presbyterate, and diaconate”—bishop, priest, and deacon—the ministry “exercised in different degrees by those who even from ancient times have been called bishops, priests, and deacons.”⁠¹⁵ That the porter and the exorcist stood on the lower rungs, and that those rungs could be reshaped or removed without touching the sacrament, the Church demonstrated in our own time: in 1972 Paul VI, by the motu proprio Ministeria quaedam, suppressed the minor orders and the subdiaconate in the Latin Church altogether, retaining reader and acolyte not as orders but as lay ministries.⁠¹⁶ The ladder the Liber Pontificalis attributed to Caius has, in the Latin rite, been largely dismantled—and the three sacramental degrees it led up to stand exactly where they always stood. The legend mythologized the scaffolding; the building it served was real, and older than the legend, and it is still standing.

Confessor, Not Martyr

For a thousand years Caius was honored as a martyr. The Liber Pontificalis, in its later form, says he “fled from the persecution of Diocletian into the crypts” and there “was crowned with martyrdom after 8 years”; the Passio Susannae sealed his blood with his niece’s.⁠¹⁷ It is a moving picture—the pope in hiding in the dark of the catacombs, at last betrayed and killed. It is also impossible, and for the plainest of reasons: the persecution he is said to have fled did not begin until 303, and Caius died in 296. A man cannot be martyred in a persecution that starts seven years after his death.

The documentary evidence tells the same story from another direction, and it is worth setting out because it is a model of how the earliest records quietly correct the later legends. The oldest liturgical calendars of the Roman church, preserved in the Chronograph of 354, come in two lists: the Depositio Martyrum, the register of the martyrs’ feasts, and the Depositio Episcoporum, the register of the bishops’ burials. Caius appears in exactly one of them, and it is the one that settles the question. He stands in the list of bishops—“X kl maii Caii in Callisti,” his deposition on 22 April in the cemetery of Callixtus—and not in the list of martyrs. The Catholic Encyclopedia draws the inference in a parenthesis and does not soften it: he is named in the Depositio Episcoporum “therefore not as a martyr.”⁠¹⁸ The very structure of the fourth-century record, which knew the difference between a bishop who died in his bed and one who died under the sword, files Caius among the former.

The earliest form of the pope-book, tellingly, agrees. Where the later recension makes Caius a martyr, the earlier one says only that he “died a confessor”—one who suffered for the faith, or stood ready to, but was not put to death.⁠¹⁹ That is almost certainly the truth of it, and it is the verdict the modern Church has returned to. When the calendar was reformed after the Second Vatican Council, the joint feast that Caius had long shared with Pope Soter—the two of them commemorated together on 22 April, an ancient pairing the martyrologies preserved—was dropped from the general calendar, and the entry in the Roman Martyrology was quietly recast. It now records, under 22 April, the burial in the cemetery of Callixtus of “Saint Caius, pope, who, fleeing the persecution of Diocletian, died as a confessor of the faith.”⁠²⁰ The official book keeps a trace of the old legend’s color—the flight from Diocletian—but withholds the title the legend most wanted to give him. Confessor, not martyr: after fifteen centuries, the Church’s own martyrology says what the fourth-century burial list said all along.

The Stone That Survived

Here at last is the thing that makes Caius, of all the obscure early popes, worth an entry of his own—for where Felix I left no stone or writing of his own, Caius left a gravestone, and it survives. When Giovanni Battista de Rossi, the founder of Christian archaeology, was excavating the Catacomb of Callixtus in the middle of the nineteenth century, he recovered from the earth of its lower galleries the broken fragments of a marble plaque and pieced them back together. Nine fragments he found and published in 1877; a tenth turned up later. Reassembled, the Greek letters spell out a burial: “Of Gaius, bishop. Deposition on the tenth day before the calends of May”—the twenty-second of April, the very day the burial lists record.⁠²¹ It is Caius’s own epitaph, the stone his own clergy set over him in 296, lost for a millennium and a half and lifted back into the light.

Read what it says, and what it does not. It names him episkopos—bishop. It does not name him martyr. The gravestone his contemporaries cut, in the peace in which he actually died, gives him the one title the earliest records everywhere give him and the medieval legend everywhere overwrote. The stone and the calendar agree against the Passio; the evidence closest to the man says, in his own century’s own letters, that he was a bishop who was buried, not a martyr who was killed.

One correction the archaeology forces on the pious tradition is worth making precisely. It is often said, loosely, that Caius lies in the Crypt of the Popes—the famous chamber in the Catacomb of Callixtus where a whole row of third-century bishops was laid, and whose original Greek epitaphs de Rossi recovered for Pontian, Anterus, Fabian, Lucius, and Eutychian, whose own stone survives there. Caius is not among those. His stone came from a separate cubiculum lower in the same cemetery, near what is called the crypt of Saint Eusebius, in a region of the catacomb that the archaeologists came to name after him—the “region of Gaius.”⁠²² He was buried, as the pope-book and the calendar both say, “in the cemetery of Calistus on the Via Appia,” among the Roman bishops of his age—but a little apart from the great papal crypt, in his own chamber, under his own stone.⁠²³ It is a fitting resting place for him: near the popes, of their company, and yet slightly to one side, in a quiet corner that would keep, better than any of theirs, the one authentic word about who he was.

What We Can Actually Say

Reduce Caius to the load-bearing evidence and the portrait is spare but not empty. A man—very possibly a Dalmatian, though the kinship to Diocletian is legend—elected bishop of Rome in December 283; pope for over twelve years, the whole of them inside the long peace between Valerian’s persecution and Diocletian’s; the shepherd of a Roman church that in these quiet decades grew large, wealthy, and elaborately organized, with a graded clergy already a generation old when he inherited it; dead on 22 April 296, in peacetime, and buried in his own chamber in the Catacomb of Callixtus under a stone that names him bishop. That is the whole of it, and every clause can be documented.

What the evidence will not bear is nearly everything that made him memorable: the imperial kinship (a coincidence of Dalmatian birth promoted to a family tie); the martyr’s crown (impossible on the calendar and denied by the oldest lists); the institution of the clerical ladder (a structure already standing in Cornelius’s day); the whole romance of Susanna and the flight through the catacombs (a fifth-century fiction built to furnish a title-church with a story). Caius is a case study in the way an age fills a silence—not with nothing, but with everything it feels such a man ought to have been. It wanted its obscure pope to be kin to the persecutor, uncle to a virgin martyr, founder of the sacred hierarchy, and a martyr himself. He was, so far as we can tell, none of these things.

He was something quieter and, in the history of the papacy, not small. He was the bishop who held Peter’s chair through the last long calm, who governed the institution in the years it needed no defending, and who died before the testing came. The legends reached for a hero and manufactured one. The truth left behind only a broken stone with a single word on it. But the word is bishop, and it is his, and it is true—which is more than can be said for the crown the centuries tried to set on his head. Sometimes the most eloquent thing a saint can leave the historian is the plainness of his own grave.

Next in the series: Pope Saint Marcellinus, the twenty-ninth (coming soon), over whose reign the Great Persecution would break.

Further Reading

For the early papacy in general, the two indispensable reference works are J. N. D. Kelly and Michael J. Walsh, The Oxford Dictionary of Popes, 2nd ed. (Oxford University Press, 2010), and Eamon Duffy, Saints and Sinners: A History of the Popes, 4th ed. (Yale University Press, 2014). The primary sources for Caius are few and public: Eusebius, The Church History, Book VII, in the translation of Arthur Cushman McGiffert, Nicene and Post-Nicene Fathers, 2nd series, vol. 1 (1890), and the Liber Pontificalis in Louise Ropes Loomis, The Book of the Popes (Columbia University Press, 1916), with the great critical edition of Louis Duchesne, Le Liber Pontificalis (Paris, 1886–1892), for the notes. On the Susanna legend and the title-church, see the entries in the Catholic Encyclopedia and Michael Lapidge, The Roman Martyrs (Oxford University Press, 2018). On the grave, the enduring authority is Giovanni Battista de Rossi, La Roma sotterranea cristiana (1864–1877), with the modern study of the site by Louis Reekmans, Le complexe cémétérial du pape Gaius dans la catacombe de Callixte (Vatican City, 1988). On the development of the clerical grades and the sacrament of Holy Orders, see the Catechism of the Catholic Church, §§1536–1600.

This post is part of an ongoing series on the popes. You can read about Saint Peter, the first pope, Saint Linus, the second pope, Saint Anacletus, the third pope, Saint Clement, the fourth pope, Saint Evaristus, the fifth pope, Saint Alexander I, the sixth pope, Saint Sixtus I, the seventh pope, Saint Telesphorus, the eighth pope, Saint Hyginus, the ninth pope, Saint Pius I, the tenth pope, Saint Anicetus, the eleventh pope, Saint Soter, the twelfth pope, Saint Eleutherius, the thirteenth pope, Saint Victor I, the fourteenth pope, Saint Zephyrinus, the fifteenth pope, Saint Callixtus I, the sixteenth pope, Saint Urban I, the seventeenth pope, Saint Pontian, the eighteenth pope, Saint Anterus, the nineteenth pope, Saint Fabian, the twentieth pope, Saint Cornelius, the twenty-first pope, Saint Lucius I, the twenty-second pope, Saint Stephen I, the twenty-third pope, Saint Sixtus II, the twenty-fourth pope, Saint Dionysius, the twenty-fifth pope, Saint Felix I, the twenty-sixth pope, and Saint Eutychian, the twenty-seventh pope.

Frequently Asked Questions

Who was Pope Saint Caius?

Caius, also spelled Gaius, was the twenty-eighth Bishop of Rome, counting Peter as first, reigning from 17 December 283 to 22 April 296. His pontificate of more than twelve years was one of the longest of the early Church, yet he is among the least documented of the popes: the historian Eusebius, a near-contemporary, gives him only a single sentence, and the Catholic Encyclopedia concedes that “nothing whatever is known of his life.” He governed the Roman church during the “Little Peace,” the long lull before the Great Persecution of Diocletian, and died in peacetime seven years before that persecution began.

Was Pope Caius really related to the Emperor Diocletian?

Almost certainly not. The Liber Pontificalis calls Caius a Dalmatian “of the family of Diocletian,” and the legendary Acts of Susanna makes him kin to the imperial house, but there is no historical basis for the claim. Diocletian was himself a Dalmatian of humble origin, and the legend appears to have promoted a shared homeland into a family tie. The whole story—Caius as kinsman of the emperor and uncle of the martyr Susanna—belongs to a late hagiographical romance, dated to around 450–500, that scholars judge to be “of no historical value.”

Did Pope Caius invent the ranks of holy orders?

No. The Liber Pontificalis credits Caius with decreeing that a man must pass in order through the grades—porter, reader, exorcist, acolyte, subdeacon, deacon, and priest—before becoming a bishop. But the graded Roman clergy already existed a full generation earlier: Pope Cornelius’s letter of around 251, quoted by Eusebius, counts the Roman church’s forty-six presbyters, seven deacons, seven subdeacons, forty-two acolytes, and fifty-two exorcists, readers, and doorkeepers. The attribution to Caius is a retrojection—the pope-book’s habit of giving an existing custom a founder. The three sacramental degrees the ladder led to—bishop, priest, and deacon—are the enduring core; the minor orders were suppressed in the Latin Church by Paul VI in 1972.

Was Pope Caius a martyr?

The evidence says no. He was venerated as a martyr for centuries, but he died in 296, seven years before Diocletian’s persecution began in 303, so he cannot have died in it. The oldest Roman calendar, the Depositio Episcoporum of 354, lists him among the buried bishops and not among the martyrs; the earliest form of the Liber Pontificalis says he “died a confessor,” and his own surviving gravestone names him only “bishop.” The current Roman Martyrology has dropped the martyr’s title and commemorates him on 22 April as a confessor of the faith.

Does Pope Caius’s tomb still exist?

Yes—remarkably, his own epitaph survives. When Giovanni Battista de Rossi excavated the Catacomb of Callixtus in the nineteenth century, he recovered and reassembled the broken fragments of Caius’s gravestone, a Greek inscription reading “Of Gaius, bishop. Deposition on the tenth day before the calends of May”—that is, 22 April. It is one of the few third-century papal epitaphs that actually survives. The stone was found not in the famous Crypt of the Popes but in a separate chamber lower in the same catacomb, in an area archaeologists named the “region of Gaius,” near the crypt of Saint Eusebius.

When is the feast of Pope Saint Caius?

His commemoration falls on 22 April, the day of his burial recorded in the fourth-century Depositio Episcoporum. For most of the Church’s history he was celebrated jointly on that day with Pope Saint Soter, an ancient pairing preserved in the martyrologies. The 1969 reform of the calendar removed both from the General Roman Calendar; Caius remains in the Roman Martyrology under 22 April, now as a confessor rather than a martyr.

Footnotes

1. 1. John Chapman, "Caius and Soter, Saints and Popes," in The Catholic Encyclopedia, vol. 3 (New York: Robert Appleton Company, 1908): "Nothing whatever is known of his life. He lived in the time of peace before the last great persecution." Available at NewAdvent.org. The 1908 encyclopedia treats Caius and his predecessor Soter in a single joint article, itself a relic of the ancient feast the two popes shared.

2. 2. The regnal dates 17 December 283 – 22 April 296 (twelve years, four months, seven days) derive from the fourth-century Liberian catalogue and are the figures modern scholarship follows; see Chapman, "Caius and Soter," Catholic Encyclopedia, vol. 3 (1908), citing Harnack after Lipsius and Lightfoot, who adds that "Eusebius is wrong in giving him fifteen years." The Liber Pontificalis gives eleven years, four months, and nine days (a variant recension, twelve days): Louise Ropes Loomis, The Book of the Popes (Liber Pontificalis) (New York: Columbia University Press, 1916), 34. On the general unreliability of the third-century Liber Pontificalis, see the introduction to Louis Duchesne, Le Liber Pontificalis (Paris: Thorin, 1886–1892), vol. 1.

3. 3. Eusebius, Historia Ecclesiastica VII.32.1, trans. Arthur Cushman McGiffert, Nicene and Post-Nicene Fathers, 2nd series, vol. 1 (New York: Christian Literature Company, 1890): "At this time, Felix, having presided over the church of Rome for five years, was succeeded by Eutychianus, but he in less than ten months left the position to Caius, who lived in our day. He held it about fifteen years, and was in turn succeeded by Marcellinus, who was overtaken by the persecution." Available at NewAdvent.org. The phrase "who lived in our day" renders the Greek kath' hēmas.

4. 4. Eusebius, Historia Ecclesiastica VII.13, "The Peace under Gallienus," trans. McGiffert, NPNF 2nd ser., vol. 1: after Valerian's capture by the Persians (c. 260), his son Gallienus "conducted the government more prudently" and "immediately restrained the persecution against us by public proclamations," directing the bishops "to perform in freedom their customary duties, in a rescript." A second decree restored the confiscated Christian cemeteries. On the period as a whole, see the survey of the "Little Peace of the Church" (c. 260–303) in the relevant entry of The Papacy: An Encyclopedia, ed. Philippe Levillain (New York: Routledge, 2002).

5. 5. Diocletian was proclaimed emperor in November 284; the first edict of the Great Persecution was issued at Nicomedia on 24 February 303 (the church there having been razed the day before). Caius died on 22 April 296, roughly seven years before the persecution began. The chronological impossibility of his martyrdom under Diocletian is noted already by Loomis, The Book of the Popes, 35 n. 2.

6. 6. Liber Pontificalis, "Gaius," in Loomis, The Book of the Popes, 34: "Gaius, by nationality a Dalmatian, of the family of Diocletian, the emperor, son of Gaius, occupied the see 11 years, 4 months and 9 days." On Diocletian's own Dalmatian origins near Salona, see J. N. D. Kelly and Michael J. Walsh, The Oxford Dictionary of Popes, 2nd ed. (Oxford: Oxford University Press, 2010), s.v. "Caius (Gaius)," who treat the imperial kinship as legendary.

7. 7. Liber Pontificalis, "Gaius" (Loomis, The Book of the Popes, 35): "He, after 11 years, was crowned with martyrdom in company with Gavinius, his brother, on account of the daughter of Gavinius the priest, whose name was Susanna." Loomis's rendering "Gavinius" represents the name standardly given as Gabinius.

8. 8. On the date (c. 450–500) and unhistorical character of the Passio Sanctae Susannae, see Michael Lapidge, The Roman Martyrs: Introduction, Translations, and Commentary (Oxford: Oxford University Press, 2018), who judges the surviving legend to be of no historical value, its family relationships fictitious, and the whole a late hagiographer's attempt to furnish personalities for the names attached to an existing title-church. Susanna's own commemoration was removed from the General Roman Calendar in 1969 "because of the legendary character" of her Acts (Calendarium Romanum, Vatican City, 1969, 134).

9. 9. The church now called Santa Susanna, at the Baths of Diocletian on the Quirinal, is documented in the fourth century as the titulus Gaii ("title of Gaius") and as the church ad duas domos ("at the two houses"); it is first attested under the name of Susanna at a Roman synod near the end of the sixth century. See Kelly and Walsh, Oxford Dictionary of Popes, s.v. "Caius"; on the Roman title-churches generally, Paul Kehr, Italia Pontificia, vol. 1 (Berlin, 1906), 61, as cited in Meier's article.

10. 10. Gabriel Meier, "Sts. Tiburtius and Susanna," in The Catholic Encyclopedia, vol. 14 (New York: Robert Appleton Company, 1912): the house of Susanna "and the adjoining one belonging to her uncle, the prefect Caius, which were near the two laurel trees, were turned into a church, later the titular church of St. Susanna ad duas domos." Available at NewAdvent.org. The article adds that "the authenticity of the Acts of Sts. Sebastian and Susanna has been rightly questioned." Note that this recension calls the Gaius of the title-church a prefect rather than the pope—evidence that the identification with Pope Caius is itself uncertain.

11. 11. Liber Pontificalis, "Gaius" (Loomis, The Book of the Popes, 35). Loomis prints two recensions in parallel; the shorter reads that a candidate "must rise from door-keeper through each rank, step by step, to the higher place," the fuller that "all the offices in the church should be thus held in turn: whoever was worthy to be bishop must first be doorkeeper, reader, exorcist, acolyte, subdeacon, deacon, priest and then be ordained bishop." The same entry adds, "He divided the districts among the deacons"—a claim the pope-book elsewhere also attaches to Fabian, and which is best treated as legend.

12. 12. Eusebius, Historia Ecclesiastica VI.43.11, quoting the letter of Pope Cornelius to Fabius of Antioch (c. 251), trans. McGiffert, NPNF 2nd series, vol. 1. The phrase "fifty-two exorcists, readers, and janitors" is standardly read as a single total of fifty-two covering all three of those minor grades together, not fifty-two exorcists alone. On this census and the size of the mid-third-century Roman church, see my entry on Pope Saint Cornelius, the twenty-first pope.

13. 13. Loomis, The Book of the Popes, 35 n. 1: Pope Cornelius, "writing thirty years before this of Novatian and the schism in the Roman church, gives the earliest known enumeration of the seven ranks in the hierarchy of the order," quoting Eusebius, Church History, VI, c. 43. The editor's own note thus undercuts the attribution of the graded hierarchy to Caius.

14. 14. On the reader (lector) as a distinct office already in Tertullian (De praescriptione haereticorum 41, c. 200), and on the subdeacons, acolytes, exorcists, and doorkeepers as first datably named as distinct grades in Cornelius's letter of 251, see McGiffert's notes to Eusebius, Historia Ecclesiastica VI.43.11, NPNF 2nd series, vol. 1. Cornelius's census implies a Roman clergy of more than one hundred and fifty men across the several grades beneath the single bishop.

15. 15. Catechism of the Catholic Church §1536 (vatican.va): "Holy Orders is the sacrament through which the mission entrusted by Christ to his apostles continues to be exercised in the Church until the end of time . . . It includes three degrees: episcopate, presbyterate, and diaconate"; and §1554 (vatican.va): "The divinely instituted ecclesiastical ministry is exercised in different degrees by those who even from ancient times have been called bishops, priests, and deacons."

16. 16. Paul VI, motu proprio Ministeria quaedam (15 August 1972): "What up to now were called minor orders are henceforth to be called ministries," of which "two . . . are to be preserved in the whole Latin Church, namely, those of reader and acolyte"; the subdiaconate "no longer exists in the Latin Church." The document thus suppressed the orders of porter and exorcist and the subdiaconate and converted lector and acolyte into lay ministries. The English text is available via EWTN; the Latin, Italian, and Spanish on vatican.va.

17. 17. Liber Pontificalis, "Gaius" (Loomis, The Book of the Popes, 35), later recension: "He fled from the persecution of Diocletian into the crypts . . . and while dwelling there was crowned with martyrdom after 8 years."

18. 18. Chapman, "Caius and Soter," Catholic Encyclopedia, vol. 3 (1908): "He is mentioned in the fourth-century 'Depositio Episcoporum' (therefore not as a martyr): X kl maii Caii in Callisti." The Depositio Episcoporum and Depositio Martyrum are preserved in the Chronograph of 354; ed. Theodor Mommsen, Chronica Minora, vol. 1, MGH Auctores Antiquissimi 9 (Berlin, 1892). In Roman reckoning "X Kalendas Maias," counting inclusively back from 1 May, is 22 April.

19. 19. Liber Pontificalis, "Gaius" (Loomis, The Book of the Popes, 35), earlier recension: "and while dwelling there died a confessor." Loomis's note (35 n. 2) states plainly that "the legend of Gaius' martyrdom is not authenticated. His name is not in the early martyrologies and the persecution of Diocletian did not begin until seven years after his death."

20. 20. Martyrologium Romanum, editio typica altera (Vatican City: Typis Vaticanis, 2004), 22 April, commemorating in the cemetery of Callixtus on the Via Appia the burial of "Saint Caius, pope, who, fleeing the persecution of Diocletian, died as a confessor of the faith" (translation from the official Latin). Caius and Soter were commemorated jointly on 22 April in the Tridentine calendar and in successive editions of the General Roman Calendar until the reform of 1969, when both were removed from the general calendar.

21. 21. The epitaph, restored, reads Γ[αΐο]υ ἐπι[σκόπου] κατ(άθεσις) πρ[ὸ ι΄] καλ(ανδῶν) μαΐω[ν]—"Of Gaius, bishop. Deposition on the [tenth] day before the calends of May" (22 April). Text: Inscriptiones Christianae Urbis Romae, n.s., IV, no. 10584. Nine of the ten surviving fragments were recovered and published by Giovanni Battista de Rossi in 1877 (La Roma sotterranea cristiana, vol. 3), a tenth by Josef Wilpert in 1910, and the whole re-edited by Antonio Ferrua in 1964; see the summary in the Oxford database The Cult of Saints in Late Antiquity, record E04739.

22. 22. The original in-situ Greek papal epitaphs recovered from the Crypt of the Popes proper belong to Pontian, Anterus, Fabian, Lucius, and Eutychian. Caius's stone came instead from a separate cubiculum in the lower part of the Catacomb of Callixtus, near the so-called crypt of Saint Eusebius, in the area the excavators named the "region of Gaius"; on the complex, see Louis Reekmans, Le complexe cémétérial du pape Gaius dans la catacombe de Callixte (Vatican City: Pontificio Istituto di Archeologia Cristiana, 1988).

23. 23. Liber Pontificalis, "Gaius" (Loomis, The Book of the Popes, 35): "He also was buried in the cemetery of Calistus on the Via Appia, April 22." Chapman's Catholic Encyclopedia article says loosely that Caius "was buried in the chapel of the popes in that cemetery," but the archaeological evidence (n. 22) places his tomb in a distinct region nearby rather than in the papal crypt itself.