The short-lived emperor Macrinus had a son whose name, inscriptions reveal, was M. Opellius Antoninus Diadumenianus.Footnote ¹ Little is known about this figure, who is remembered through brief references in the late Roman breviaries and in Herodian, and in a short biography in the collection of imperial lives now known as the Historia Augusta (= HA). In 1889, Dessau argued that the lives of the Historia Augusta, which present themselves as written by six different authors in the Age of Constantine, were in fact written by a single writer closer to the year 400, an argument that has now all but prevailed in scholarly circles.Footnote ² Some of the biographies depend on reliable sources, at least in part, and thus can provide actual historical information; others do not, and are mostly or entirely the result of authorial invention. The life of Diadumenianus fits clearly in the latter category. The secondary lives (Nebenviten) of the Historia Augusta contain no original information, but rather are constructed from a combination of information derived from their ‘parent’ life and invented fiction. So, for example, the life of the Caesar Aelius combines information from the life of Hadrian with fiction, the life of the usurper Avidius Cassius combines information from the life of Marcus Aurelius with fiction, and the lives of Pescennius Niger and Clodius Albinus combine information from the life of Severus with fiction. In the case of Diadumenianus, the life is even more thoroughly fictional, since the life of Macrinus from which it is derived is itself a kind of secondary life; Cameron suggests that Marius Maximus, the probable source for the author of the Historia Augusta, treated Macrinus as a usurper in the life of Elagabalus.Footnote ³ Almost every detail of the life of Diadumenianus is therefore the fictive invention of the author.

Eutropius, Aurelius Victor and the anonymous Epitome de Caesaribus curiously preserve the name of Diadumenianus as Diadumenus, an error which must derive from their common ancestor, the lost work known as Enmann's Kaisergeschichte.Footnote ⁴ The author of the Historia Augusta made use of three of the works—Eutropius, Victor and the Kaisergeschichte—that use the incorrect Diadumenus, but he also used Herodian, who preserves the correct spelling Diadumenianus (5.4.12).Footnote ⁵ Herodian 5.3–4, in particular, where the name is spelled correctly, is clearly the source for the Historia Augusta of the narrative of the death of Macrinus (HA, Macr. 8.3–10.4). Nevertheless, the author uses the incorrect Diadumenus throughout. It is not clear what motivated the author's choice of the wrong spelling of the name; certainly, when investigating the Historia Augusta, laziness and ignorance should never be ruled out as potential causes. But whether he wrote Diadumenus purposefully or fortuitously, he seems to have been inspired in his discussion of the young Caesar by another Diadumenus, the young lover of the poet Martial who is featured in three of his epigrams (3.65, 5.46 and 6.34). Inspired by the coincidence of names, the author playfully transforms the Caesar into an elegiac lover.

The author of the Historia Augusta engages with Martial elsewhere in several places. The Caesar Aelius, who was adopted by Hadrian in 136 but died before taking the throne, is depicted as a pleasure-seeking wastrel; in addition to having Apicius and Ovid's Amores always at his bedside, he is said to have proclaimed that Martial was his Virgil (… idem Martialem, epigrammaticum poetam, Vergilium suum dixisse, HA, Ael. 5.9). In the life of Alexander Severus, the author claims that the emperor ate hare daily, and then quotes an epigram of Martial on the folk wisdom that connects the eating of hare with physical attractiveness (HA, Alex. Sev. 38.2).Footnote ⁶ The fictitious claim of hare consumption must have been concocted with the Martial poem in mind. Perhaps he was simply inspired by the coincidence of names with Gargilius Martialis, a second-century botanist whom he cites as a biographer immediately before (HA, Alex. Sev. 37.9).Footnote ⁷ It has also been convincingly suggested that the phrase uendere fumum, used by the Historia Augusta several times to describe corrupt officials taking bribes under false pretenses (HA, Ant. Pius 11.1, Heliogab. 10.3, Heliogab. 15.1, Alex. Sev. 23.8, Alex. Sev. 35.5 and Alex. Sev. 67.2), derives ultimately from Martial 4.5.7.Footnote ⁸ The most elaborate use of the phrase in the Historia Augusta features the corrupt fictitious official Verconius Turinus, whose name evokes incense, burned at a stake heaped around with straw and wet wood. The herald announces: ‘the seller of smoke is punished by smoke’ (fumo punitur qui uendidit fumum, HA, Alex. Sev. 35.5–36.3). It occurs in close proximity to the previously discussed passages alluding to Martial, which encourages us to accept the connection here as well. Thus the author of the Historia Augusta has read and expects his audience to be familiar with Martial.

Three poems of Martial feature Diadumenus, a young man who is the object of the poet's erotic attention.Footnote ⁹ The first, 3.65, celebrates the sweetness of his kisses with comparison to other sweet smells. In the second, 5.46, Martial explains that he prefers stolen kisses to freely offered ones. The third, 6.34, alludes to poems of Catullus addressed to Lesbia (5 and 7) and to Juventius (99), in requesting a large number of kisses. The Historia Augusta in the life of Diadumenus engages both with the general portrait of an elegiac lover and with specific details from these poems.

Syme notes that the author of the Historia Augusta curiously wavers when referring to the age of Diadumenianus.Footnote ¹⁰ He was in fact eight years old at the time of Macrinus’ accession. In the life of Elagabalus, however, the author condemns Diadumenianus as ‘dissipated and cruel’ (luxurioso et crudeli, HA, Heliogab. 2.3). Later Elagabalus attacks the memory of Diadumenianus in a bizarre way: he claims that the Caesar had been living an extravagant life, but had reformed and become quite serious and sober (HA, Heliogab. 8.4). Elagabalus also forced certain writers to describe Diadumenianus’ profligate behaviour in detail, which the author of the Historia Augusta claims to find too shameful to report (HA, Heliogab. 8.5). Clearly Diadumenianus must be an adulescens for these criticisms to make sense. In the previous lives, however, his actual age is mostly presented correctly. He is called puer twice at the end of the Macrinus (HA, Macr. 14.1, 14.2), is named puer seven more times in the so-called Diadumenus (HA, Diad. 1.1, 1.3, 1.4, 1.5, 2.5, 3.2, 3.3), and is twice referred to as puerulus (HA, Diad. 2.2, 6.1). But traces of the older Diadumenianus remain in the physical description of the Caesar, where he is depicted as an eroticized adolescent (HA, Diad. 4.2), and in a description of a name change occurring ‘when he grew up’ (ubi adoleuit, HA, Diad. 4.4). Syme argues that this is evidence for the order of composition of the lives: the author wrote the life of Elagabalus first, in ignorance of the Caesar's age, and only after realizing that he was a boy did he write the life of Macrinus and the life of Diadumenus. But the author's selective presentation of Diadumenianus as an adolescent is purposeful. In the life of Elagabalus, he is an adolescent so that the author can create a foil to Elagabalus that throws into relief Elagabalus’ inversion of norms, his celebration of vice, and his condemnation of virtues. In the life of Diadumenus, the Caesar is temporarily an adolescent in order to allude to the elegiac lover in Martial's poems.

The physical description of the boy emperor particularly highlights the elegiac nature of his portrayal:Footnote ¹¹ puer fuit omnium speciosissimus, statura longiuscula, crine flauo, nigris oculis, naso deducto, ad omnem decorem mento composito, ore ad oscula parato, fortis naturaliter, exercitio delicatior (HA, Diad. 3.2). The last three attributes are of particular interest. Diadumenus’ ‘mouth ready for kisses’ evokes a theme common to all three of Martial's Diadumenus poems. In 3.65, Martial celebrates the fragrance of the boy's grudging kisses: hoc tua, saeue puer Diadumene, basia fragrant. | quid si tota dares illa sine inuidia? In 5.45, the poet explains his preference for stolen kisses, basia … quae luctantia carpsi. And 6.34 is in conversation with the kiss poems of Catullus: basia da nobis, Diadumene, pressa. ‘quot’ inquis?

Since the kisses point toward an elegiac portrait, the final parts of the description, fortis naturaliter, exercitio delicatior, ought also to be re-examined. Translations vary, but seem to have been made with the image of an eight-year-old in mind, such as Chastagnol (‘à sa robustesse naturelle s'alliait une grande élégance dans les exercices physiques’) or Birley (‘he was naturally strong, though pampered by his upbringing’) or Hohl (‘er war von Natur stark, aber durch körperliche Übung recht elegant’).Footnote ¹² A contrast is clearly meant, and emphasized by chiasmus: Diadumenus was fortis by nature, by practice he was delicatior. In an erotic context, to be fortis is to play the masculine role in sex effectively (TLL 6.1.1148.36), as in Ovid's advice to have multiple mistresses, … amicas | fortior est, plures siquis habere potest (Rem. am. 441–2), or in Juvenal's discussion of a deceitful cinaedus who plans to commit adultery, hic erit in lecto fortissimus (6.O25).Footnote ¹³ The word delicatus, of course, quite commonly refers to effeminacy even outside of erotic contexts; in the Historia Augusta, the adjective is used of the boy favourites of Trajan (HA, Hadr. 4.5.2) and of Herodes, the son of Odenathus, ‘the most effeminate of men, entirely Eastern and addicted to Greek luxury’ (homo omnium delicatissimus et prorsus orientalis et Graecae luxuriae, HA, Tyr. Trig. 16.1). So I propose we translate ‘naturally virile, but more effeminate through practice’, a playful conflation of the Diadumenus of Martial with the Caesar ‘Diadumenus’.

A similar conflation of the Historia Augusta Diadumenus with Martial's is evident in the use of saeuitia and related words. While the use of saeuus, saeuitia or saeuire to refer to tyrants in the Historia Augusta is common (for example HA, Comm. 3.9, Max. 21.1, Tyr. Trig. 10.1), the words also carry an erotic, elegiac connotation, often applied to the dura puella by Propertius and Tibullus.Footnote ¹⁴ Catullus refers to the saeuitia of his lover Juventius (Catull. 99), and Martial calls his lover saeue puer Diadumene in 3.65. The author of the Historia Augusta invents a conspiracy against Macrinus in order to provide a setting for Diadumenus to express his own saeuitia. After Macrinus has pardoned the accomplices of the conspirators, the author offers us a fictitious letter written by Diadumenus in which he decries his father's decision to leave them unpunished. Many authors, we are told, claimed that the Caesar was ‘cruel beyond his years’ (ultra aetatem saeuisse, HA, Diad. 8.3). They will prove to be cruel enemies, he complains, if they are not executed at once. The saeuitia of the reluctant lover is contrasted with the more terrifying saeuitia of the ruler.

The scenario of the letter itself may also allude to one of the Diadumenus poems, 5.46:

The author of the Historia Augusta has mapped this struggle over kisses from a reluctant lover onto his invented narrative of a struggle over the state. Diadumenus’ complaint to his father against his choice for leniency argues that it will not benefit him, for they will never love nor fear him in the future: ‘First of all, they are not able to love you now, having been wounded by suspicion, and second, those who have forgotten their ancient friendship and have joined your bitterest enemies will be crueller enemies’ (nam primum omnium iam te exulcerati suspicionibus amare non possunt. deinde crudeliores inimici sunt, qui obliti ueteris familiaritatis se inimicissimis tuis iunxerunt, HA, Diad. 8.6). There is only one solution: ‘they must be beaten’ (feriendi sunt isti, HA, Diad. 8.8). Thus struggle and beating, and a lack of love and fear, are found in each passage.

At the conclusion of the fictitious letter which the author attributes to the Caesar, he adds that the letter may have been written not by Diadumenus himself but rather, according to some, by ‘his teacher Caelianus, formerly a rhetor in Africa’ (quidam magistri eius Caeliani ferunt, Afri quondam rhetoris, 8.9). Martial's last Diadumenus epigram (6.34) is followed by an epigram (6.35) which mocks his frequent target, the rhetor Caecilianus; the cognomen is particularly frequent in Africa.Footnote ¹⁵ The epigram notes that the judge had granted Caecilianus seven water clocks (clepsydrae) worth of time to make his case tediously; Martial wishes that Caecilianus, rather than gulping down glasses of water as he drones on and on, would drink directly from the clock, both soothing his throat and hastening the end of his protracted speech. Just as the author of the Historia Augusta has made Diadumenianus into a Diadumenus, perhaps he has made Martial's orator Caecilianus into a Caecilius to round out the life.

The sources that the author had at hand revealed that the life of Diadumenianus ‘contained nothing memorable’ (nihil habet uita memorabile, HA, Diad. 1.1), and so he was forced to invent. As often, the author turned to literature to fill out his biographies. Inspired by the coincidence of names, the author creates a variety of allusions and connections to the work of Martial for a knowledgeable audience to discover and enjoy. The knowledgeable reader looks to the life not to learn the details of the brief career of an insignificant Caesar but as a puzzle of literary references to be recognized and enjoyed.