II CYCLES AND STRUCTURE

DN's form is inseparable from its content (see Table 1). The text is almost a ring composition as it stands, beginning with the smallest form of human life, the embryo, then taking the reader all the way out to the cosmos, and ending with the smallest units of time structuring daily life. The organisation thus enacts the lifecycle, which can also be linked to its status as a munus in cycles of reciprocity among friends. Emerging from a polyphony of views on human generation, the teachings of Pythagoras are singled out as the most credible, in particular the notion that three musical harmonies govern our gestation (micro scale) and the music of the celestial spheres (macro scale). This relationship, illustrated through an excursus on Pythagoreanism, rearticulates the text's structure, but also subtly suggests the contingency of an individual's experience as they pass through these cycles.

Table 1 DN's Contents

The very first word of DN, munera, evokes a complex of ideas around cycles — social, political and temporal. The term munus is multidimensional: its meanings include ‘gift’, ‘duty’ and ‘obligation’, encompassing at once the private, civic and divine spheres.Footnote ¹⁴ First and perhaps foremost, however, munus indicates the reciprocities that structure Roman social life: the obligations binding friends to one another (including patrons and clients), the responsibilities of citizens to the state and vice versa, and the duties humans undertake to honour the gods.

In the late Republic, munus began to be used, specifically, as a term for a book-gift (often designated a ‘libellus’).Footnote ¹⁵ In this context, munus indicates ‘a path of circular reciprocity’, Stroup argues, as the objects exchanged no longer constitute a ‘monetary transaction’ and enter a different sphere; the gift takes on the status of ‘pricelessness’, since its monetary value can no longer be determined by comparison with similar objects.Footnote ¹⁶ The first sentence of DN activates these associations:

Because of Censorinus’ own limited means, he has created a gift for Caerellius using his own ‘wealth’ (‘comparatum meis opibus’, 1.5), his knowledge, which is, in a sense, priceless. The book is part and parcel of Censorinus’ own sacrifice to Caerellius’ genius (another munus, in the sense of ‘duty’), all to thank his patron for a friendship that has brought him honour, respect and protection (3.6), gifts by their very nature classed outside the realm of monetary value. DN portrays the genius as divine, and to sacrifice to one's genius constitutes an annual duty, ‘munus annale’ (DN 2.2). By writing DN and sacrificing to Caerellius’ genius on his birthday (3.5–6), Censorinus suggests a parallelism in reciprocity at a human and divine level.Footnote ¹⁷

Reciprocity and cyclicality also emerge in DN 1's echo of Horace's Carm. 4.8, a birthday poem dedicated to a man named Censorinus, either Lucius Marcius Censorinus (cos. 39 b.c.e.) or his son Gaius Marcius Censorinus (cos. 8 b.c.e.).Footnote ¹⁸ Their ancestor, likewise, Lucius Marcius Censorinus (cos. 149 b.c.e.), appears at DN 17.11, the very same chapter in which Horace's Carmen saeculare is quoted directly, tying the intertextual knot even tighter.Footnote ¹⁹ Like DN 1, Carm. 4.8 also begins with luxurious objects (bowls, bronzes, tripods) Horace would present to Censorinus on his birthday if he were a different — wealthier — kind of artist (4.8.1–8). He explains, ‘sed non haec mihi uis, nec tibi talium / res est aut animus deliciarum egens: / gaudes carminibus; carmina possumus / donare, et pretium dicere muneri’ (‘but these things are not in my power, and you are not concerned with such luxuries, nor do you have a mind that needs them. You enjoy songs; we can give you songs and assign a price to the gift’).Footnote ²⁰ Carm. 4.8 thus plays with similar themes, especially the trope of the literary munus and its value in a cycle of reciprocity. Censorinus, the client-author, now fills Horace's position, while Caerellius is implicitly likened to the illustrious, consular Censorinus.Footnote ²¹ The configuration suggests how family fortunes may rise and fall — the descendant of consuls becomes a new man's client, a new man ascends to the ranks of bygone heroes.

Going forward, the text then moves chronologically through the process of generation, employing a doxographic approach to questions about gestation. After conception come competing views on pregnancy, foetal development and birth (4–7). On the origin of human seed, for example, ‘inter sapientiae professores non constat’ (‘there is no agreement among teachers of philosophy’), listing Parmenides, Hippon, Anaxagoras, Democritus and Alcmaeon, Diogenes, Empedocles and Epicurus (5.2–4); he offers no resolution. The same is true of the formation of the foetus, its nourishment, the origins of sexual difference, family resemblance and twins (DN 6). Yet DN soon abandons this doxographic style and moves outward to the zodiac and astrology (8), the music of the spheres, how cosmic harmony ties into our bodily systems and growth in the womb (10–13) and, finally, numerology and the lifespan (14). In these fourteen books, Censorinus takes us on a journey from the microcosm of the womb out to the farthest reaches of the universe, beginning with conflicting views (esp. DN 5–7), then valorising Pythagorean teachings on embryology, music and the cosmos (9–13), before turning to ‘crisis’ years in the lifespan.

Pythagoreanism forms the central axis of these chapters, the only philosophical viewpoint DN explicitly endorses.Footnote ²² As Freyburger contends, this preference may be an index of Neopythagoreanism's contemporary popularity.Footnote ²³ Censorinus probably read works (or summaries thereof) that privileged Pythagoras as a mythical initiator of the philosophical tradition, and observed how Pythagorean numerology, astronomy and music theory project a coherent vision of the cosmos and its building blocks.Footnote ²⁴ Perhaps Censorinus was also influenced by the prestige awarded to Pythagorean figures by the Severans. Not long before DN was written, Philostratus published the first Neopythagorean biography, the Life of Apollonius of Tyana, purportedly commissioned by the empress Julia Domna herself.Footnote ²⁵ Third-century texts also suggest heightened interest in Pythagoras, who became the subject of a spate of biographies.Footnote ²⁶

Immersed in this intellectual milieu, Censorinus delights in the opportunity to elucidate for his patron Pythagoras’ incredible discovery (DN 10.8), that is, the relationship between harmonics and birth. The topic emerges from a dispute on gestational duration at 7.5–7 (that is, in what months of pregnancy is a foetus viable?). He draws on Varro's (now lost) Tubero, de origine humana to explain Pythagorean teachings on this topic: ‘quae quidem ratio praecipue recipienda ad ueritatem proxime uidetur accedere’ (‘that position should certainly be accepted as it seems to come closest to the truth’).Footnote ²⁷ According to Pythagoras, there were two types of pregnancies, seven and ten months, each corresponding to a different harmonic ratio, which guide the successive stages of foetal development. Compared with Diogenes’ and Hippon's opinions, Pythagoras’ view is ‘credibilius’ (‘more believable’).Footnote ²⁸

This relationship between foetal development and music — illustrated using arithmetic — creates the opportunity to present birth/days as embedded in a stable, harmonious cosmos. Censorinus explains, ‘qui secreta naturae seruando repperit phthongos musicorum conuenire ad rationem numerorum’ (‘by observing the secrets of nature [Pythagoras] discovered that musicians’ notes [i.e., harmonies] correspond to numerical ratios’).Footnote ²⁹ The musical harmonies of the fourth, fifth and octave (in our terms), the three ‘symphoniae simplices ac primae’ (‘simple and primary harmonies’),Footnote ³⁰ correspond, respectively, to the ratios of 4:3, 3:2 and 2:1, which he proved with experiments on stringed and wind instruments.Footnote ³¹ Pythagoras explained how these same ratios and harmonies govern the time it takes a foetus to gestate, so birth is keyed to an overarching, harmonic structure in nature. Doctors have confirmed these timelines, verifying the Pythagorean numerological understanding of ‘nature's secrets’ (‘arcana naturae’).Footnote ³²

For Censorinus, musical harmony's effect on birth is a by-product of its power over bodies, souls and immanence in the universe. As with gestational stages, doctors also offer a kind of proof for the relationship between music, soul and body. The Greek physician Asclepiades healed mentally ill patients ‘through harmony (‘per symphonian’), and Herophilus, too, believed that our pulse responded to musical rhythm (DN 12.4). Censorinus concludes, ‘Itaque si et in corporis et in animi motu est harmonia, procul dubio a natalibus nostris musica non est aliena’ (‘And so if there is harmony in the movement of both our body and soul, there is little doubt that music is related to birthdays’).Footnote ³³ We can piece together the chain of connections as follows: (1) harmony pervades the body and soul; (2) it affects the time of our birth; and (3) is therefore important to birthdays as well.Footnote ³⁴

The connections among bodies, music and the stars receives its clearest articulation when Censorinus turns to the ‘music of the spheres’, a popular idea throughout Antiquity and long after.Footnote ³⁵ The distance of the seven planets (‘septem stellae’) from one another corresponds precisely to the musical ratios outlined above. Pythagoras ‘measured’ the distance from the earth to every stella (DN 13.2), and as Censorinus proceeds planet by planet, we learn that the distance from earth to the vault of the heavens corresponds to a musical octave, from the earth to the sun, a fifth, and from the sun to the moon, a fourth (13.2–4).Footnote ³⁶ As the planets move, they harmonise to create ‘dulcissimam… melodian’ (‘the sweetest melody’), which human ears cannot detect.Footnote ³⁷ Thus the same set of intervals that govern foetal development and birth exist among earth, sun and moon, with the sun serving as the pivot. This vision is also deeply rooted in astrology, which becomes explicit when Censorinus explains that the ‘septem stellae’ govern the nativities (‘geneses’) of humans (13.1).Footnote ³⁸

DN's Pythagorean turn mostly — but not completely — suppresses dissenting views. Censorinus appears committed to conveying an image of a regular, perfect cosmos, glossing over messy arithmetic and abandoning the heavily doxographic style of earlier chapters. In doing so, he works towards a kind of ‘harmony’ by moving from a plural to a unitary interpretative framework. He shows not only how three basic harmonic ratios affect our earliest beginnings, from conception to birth, but also how they operate at the level of the ‘septem stellae’ in relation to the sun. Pythagoras ‘showed that the whole universe is harmonic’ (‘hunc omnem mundum ἐναρμόνιον esse ostendit’).Footnote ³⁹ At the same time, however, careful attention to his language, particularly in DN 9, suggests he is working with ideas that are more or less credible (‘credibilius’). He ultimately endorses the Pythagorean interpretation in terms of competitive plausibility (‘ad ueritatem proxime uidetur accedere’).Footnote ⁴⁰

On the most basic level, DN takes us from the moment of conception through the growth of a foetus and out to cosmic space/time and eternity, before narrowing down gradually to the smallest units of time. The micro–macro features of these early chapters on generation and Pythagoreanism are rearticulated in the text's overall structure. Having demonstrated how birth figures in a harmonious cosmos, Censorinus guides us into a discussion of the marking and dividing of time, as he moves towards fulfilling the promise to elucidate his patron's birth(day). DN 16–24 provides a wealth of antiquarian information to aid in this endeavour, an effort that involves coordinating, layering and nesting systems and units. DN 16 begins with the concept of eternity (aeuum), mirroring the vastness of DN 13 on the Pythagorean universe. From here, we encounter diminishing spans of time: the ‘age/century’, saeculum (17), ‘great years’, anni maiores, (18) and the year, annus (19). The cultural contingency of these units prompts a chapter on calendars, especially the Roman calendar (20) and another on ‘global’ historical chronology (21). Having provided this background, he then treats shorter and shorter spans of time, with chapters on months (22), days (23) and divisions of a day (24). The structure suggests the lifecycle through its largely symmetrical construction.

The text's symmetrical features may have been even more obvious in its original form. In DN 16–24, Censorinus lays the groundwork for an explicit discussion of the day of Caerellius’ birth(day), which emerges clearly in an articulation of his interlocking goals (16.1):

The phrase ‘tempus… hodiernum’ here refers to Caerellius’ birthday, when Censorinus means him to read the uolumen he sent as a gift. By elucidating the time of Caerellius’ birthday, it is possible then to work one's way backward (based on Caerellius’ age), and thus make known the precise date of his birth.Footnote ⁴¹ In a way that is hard to capture in an English translation, the passage highlights the ambiguity of the word natalis, which can mean both ‘birthday’ and ‘(day of) birth’.Footnote ⁴² While Censorinus does discuss the current year (DN 21), the fact that he never discusses the day explicitly may suggest we are missing some final sections, despite the work's overall cohesion as it stands.Footnote ⁴³ If the text is indeed incomplete, its original ending likely delivered on Censorinus’ promise to make known the precise time of his patron's dies natalis and perhaps discussed features of his horoscope.Footnote ⁴⁴ Given the way DN 24 drops off rather abruptly, lacking the deferential conclusion one would expect from the rest of the work, I would suggest that the original ending might have praised Caerellius in the manner of DN 1 and 15, completing the symmetrical structure. This (hypothetical) ending, however, was lost or excised sometime before the eighth century, because from that time onwards DN is transmitted in the twenty-four chapters that have come down to us.

There are many ways we might think about the cyclical organisation of DN.Footnote ⁴⁵ As a munus, it is implicated in a gift-exchange cycle of patronage and friendship. The discussion of the zodiac and the music of the spheres reinforces the power of circles in nature. The work's arrangement suggests the lifecycle, the process of growing up and growing old, as we begin with the cradle of human life, the womb and conception, and gradually come to recognise the individual's place in the cosmos and in human institutions — as time gradually runs out.Footnote ⁴⁶ Censorinus himself explicitly articulates a cyclical view of life, citing philosophers from Pythagoras to Theophrastus, ‘aiunt principium fuisse nullum, sed orbem esse quendam generantium nascentiumque, in quo uniuscuiusque geniti initium simul et finis esse uideatur’ (‘they say that there was no origin point, but that there is some sort of cycle of things generating and coming to birth, in which the beginning and end of each living thing seem to exist at the same time’).Footnote ⁴⁷ The text's journey through smaller and smaller units of time (DN 19, 22–4) is also reminiscent of a conventional style of funerary epitaph, wherein the deceased's life is measured out quite literally in years, months, days and even hours.Footnote ⁴⁸ Cosmic, social and biological cycles are thus interwoven.

While Censorinus endorses Pythagorean ideas, his terms subtly impart an element of contingency to DN's tidy picture of the universe and the nesting or interlocking cycles discussed above. In a way, Pythagoreanism does too — through the doctrine of metempsychosis or transmigration, with its implication of the soul's variable, situated experience of biological cycles. In other words, death means rebirth in another body, as suggested by the cycle (orbis) posited at DN 4.4. Ovid's Pythagoras of Metamorphoses 15 comes to mind, where he expounds on the ‘variability of being’Footnote ⁴⁹: ‘morte carent animae semperque priore relicta / sede nouis domibus uiuunt habitantque receptae’ (‘our souls are deathless, and as ever, when they have abandoned their previous resting place, inhabit the bodies that have received them and dwell in their new homes’).Footnote ⁵⁰ Although Censorinus does not explicitly address metempsychosis, the philosophical centrality of this idea is inescapable, particularly since the question of ensoulment was so central to ancient debates about foetal development, a subject to which DN devotes considerable attention.Footnote ⁵¹ In this regard, the harmony of the Pythagorean cosmos and the stability of this cycle belie the instability of our flesh, or the variable, changeable ‘home’ where souls reside. Like the epistemic uncertainty of his chapters on generation, this notion rearticulates the tension between unity and plurality and resonates with DN's encyclopaedic features, to which we now shall turn.

III CATEGORISING DE DIE NATALI

Variability also characterises DN's experimentation with genre. To achieve a comprehensive understanding of the dies natalis, the text moves from encomium to doxography to Pythagorean tutorial to antiquarian exposition. DN belongs to a ‘spectrum’ of encyclopaedic texts from the Roman Empire, among antiquarian miscellanies, compendia and florilegia. In their own unique ways, these texts promote ‘itemisation, analysis, ordering, hierarchisation, synthesis, synopsis’, often engaging mimetically with large-scale phenomena they seek to elucidate (from literary culture to the animal kingdom).Footnote ⁵² DN's approach to comprehensiveness and heterogeneity comes into focus by comparison with other (roughly contemporary) projects on this ‘spectrum’. At the same time, the text's outward-looking perspective contrasts with its centripetal focus on Caerellius and Rome.Footnote ⁵³ The following section explores these generic and structural features and how they contribute to DN's message and orientation in light of the analysis in Section II.

While Censorinus assiduously cleaves to his main themes, birth and time, DN exemplifies the literary and cultural value placed on uarietas (‘variety’), an observation which extends from his content to genre and diction.Footnote ⁵⁴ Indeed, the work is not so much ‘zwischen Rhetorik und Wissenschaft’, as both and more.Footnote ⁵⁵ To make his point, Censorinus brings together a range of ideas and information (antiquarian, philosophical, religious, astrological, medical, scientific), and to a certain extent, genres as well. The overall impression is one of abundance, copia, sometimes even messiness (when authorities are not in agreement), which contrasts with the text's rather tight structure.Footnote ⁵⁶ As a comprehensive guide to the dies natalis (particularly, Caerellius’ dies natalis), DN, like many other encyclopaedic texts of the time, may be understood as a response to ‘the fragmentation of knowledge and the collapse of the authority of books by reuniting, within a single text or set of texts, materials otherwise scattered through many others’.Footnote ⁵⁷ We should see Censorinus’ reliance on Varro, one of Rome's ur-compilers, in this context. Roman encyclopaedism was a response to the conditions of ancient book culture and proliferating knowledge, one with a range of political implications.

By the end of the second century, the encyclopaedic impulse was generating a range of expansive, imaginative works, from Aulus Gellius’ Noctes Atticae in Latin to Athenaeus’ Deipnosophistae and Aelian's De natura animalium in Greek. These works often include self-conscious reflection on the scholarly process of assembly. Gellius, for example, opens with a description of his (seemingly) unsystematic research and writing method, revealing a world of intellectual and literary profusion. Anything interesting he heard or read was simply jotted down in his notes (‘… indistincte atque promisce annotabam…’, praef. 2). During long winter evenings in Attica (hence the title), Gellius explains that he assembled his notes into commentarii (‘collections’, ‘commentaries’, ‘compendia’), reproducing the haphazard ordering of their initial reception.Footnote ⁵⁸ Much can be (and has been) said of this preface, but for our purposes, one observation is helpful: Gellius, at times self-deprecating, presents his work as the product of culling and compiling bits and pieces of knowledge for later use, when his original sources are not at hand. His method is part of his aesthetics of uarietas (or poikilia). If there is an organising principle, the preface suggests the answer lies in Gellius’ practice of listening, reading, thinking and recording.Footnote ⁵⁹

Censorinus also begins with a meta-commentary, both swearing off traditional birthday encomium and including a bit of it too. Praise of Caerellius is quite literally sandwiched in the middle of his explanation, subtly reproducing the overall structure of the work (1.6):

Censorinus situates himself in a similar intellectual ecosystem to Gellius, but as a user of commentarii, rather than a producer. His self-deprecating description of his method and DN's scope curtail anticipation of traditional thematic material and genres, as well as any expectation of comprehensiveness (‘aliquantum uolumen’, ‘quasdam quaestiunculas’), even as the work implicitly presents itself as a complete guide to Caerellius’ birth/day.Footnote ⁶¹

The interplay between content and form in DN benefits from comparison with other contemporary, Greek language encyclopaedic projects. For example, Aelian's De natura animalium, a close contemporary to DN, is a seeming hodgepodge of anecdotes about animals that appears to deny any formal, organising principle. But this would be to miss the point: the structure mirrors nature's variety, not unlike Gellius’ world of literary profusion.Footnote ⁶² Within this abundance, the author himself appears (‘I’), exerting his own kind of ‘centripetal’ force, comparable in some ways both to Censorinus’ role as compiler and Caerellius’ function as anchor of DN. Smith argues that Aelian's text should be seen as ‘a compelling illustration of the tenuousness of a singular authority as it struggles to assert itself, constantly at risk of being overwhelmed by the chorus of voices from the past’ — in other words, it is fundamentally ‘suspended between the individual and the multiplicity’.Footnote ⁶³ The tension between unity and plurality, or ‘the individual and the multiplicity’, also characterises DN, as Section II argued. Censorinus’ enumeration of philosophical and scientific viewpoints suggests ‘the impossibility of totalisation’, to quote König and Whitmarsh, an acknowledgment of the range of potentially conflicting responses to important questions.Footnote ⁶⁴ Encyclopaedic texts are fertile ground for exploring the contours of authority, the proliferation of knowledge and the human capacity (asymptotic though it may be) to capture the non-human environment using our words and ideas.

Ordering knowledge always has political stakes. Indeed, numerous studies have argued that encyclopaedic projects are inherently imperial.Footnote ⁶⁵ The conditions of knowledge in Censorinus’ milieu and the totalising projects of his contemporaries align with attitudes towards the Roman Empire as encompassing the oikoumenē. In this regard, a Latin text by Lucius Ampelius, Liber memorialis, is a worthwhile comparandum, especially given its structure and scope.Footnote ⁶⁶ The work begins with a brief dedication to someone named Macrinus, possibly the emperor of 217–218 c.e., who was, incidentally, the first equestrian emperor.Footnote ⁶⁷ Although not explicitly stated, Ampelius’ dedication suggests the text was some kind of gift, perhaps from teacher to pupil:

This statement basically maps the text's organisation, which is also cosmic in scope.Footnote ⁶⁸ Ampelius begins with the four elements (1), then describes the zodiacal signs and cosmos (2–5), earth (6), oceans (7), gods (9), empires (10–16), culminating in Rome, then Roman history (17–29), Roman victories (30–47) and finally its civic institutions (48–50). Like Censorinus, he similarly experiments with scale; Liber memorialis moves from the outermost reaches of the cosmos to the earth, then narrowing to empires and ‘great’ men, with Rome as the teleological endpoint.

Ampelius’ selection of material also encompasses basic astrology, theology, anthropology and history, but unlike DN, his text demonstrates no sense of epistemic tension or uncertainty. It omits any diversity of opinion or perspective. Instead, the work is a ‘vehicle of authoritative, uncontentious, definitive knowledge’, projecting a vision of a static imperial order.Footnote ⁶⁹ It covers little of Roman history after Augustus (a quasi-messianic figure), though composed well over a century after his death.Footnote ⁷⁰ The work's stable, teleological outlook may be a reaction to the profusion that stimulated the encyclopaedic impulse in authors such as Gellius, Athenaeus or Censorinus. Liber memorialis offers up to its dedicatee a static vision of the world and its knowledge as something one can package up and possess (after all, it too is a gift of sorts). The political implications of this observation become especially rich should the dedication in fact refer to the Macrinus who briefly ruled Rome.

The ‘world of knowledge’ is an apt phrase to describe the preoccupation of Censorinus and these other authors, whose texts often have mimetic features (imitating nature, literary profusion etc.), in which the boundaries of imperial space and knowledge are always under negotiation. I would suggest this is part of the ‘reality’ and impetus beneath Ampelius’ listicle. In these texts, Rome and Roman power are often at issue in some way, whether from the perspective of an outsider looking in or insider looking out.Footnote ⁷¹ Encyclopaedic texts show us intellectuals from across the Empire working out the contours of their worlds, reproducing and exploring tensions that arise under the conditions of knowledge in an empire stretching from Britain to the Middle East.Footnote ⁷² The choice to write in an encyclopaedic genre can also serve as a meta-commentary on their experiences of knowing in this imperial context.

Censorinus locates his patron at the very centre of a vast empire — of knowledge, space and time. By reserving DN 15 for praise of Caerellius, the central hinge between the chapters on birth and time, he places him in the most ‘cosmic’, exalted site in the work, essentially sandwiched between the stars and eternity.Footnote ⁷³ This chapter, which departs in tone and content from surrounding chapters, also provides some tantalising details about Caerellius’ career, concluding with a praeteritio, which points to the topic of time and time measurement (DN 15.4–6):

Despite reproducing certain conventional features of birthday literature, the manner in which DN praises Caerellius is devoid of the kind of biographical information one might find in a birthday speech.Footnote ⁷⁴ Through a series of rhetorical questions, the rest of DN 15 vaguely sketches the trajectory of Caerellius’ upward mobility, but not a word as to basic questions of origin and identity — not even the name of his native city. In this way, Censorinus effectively glosses over another meaning of ‘birth’, that is, parentage and kinship. Traditional elements of Roman birthday celebrations are not primarily the focus. What is important, DN suggests, is when you are born, not to whom you are born, perhaps a cleverly oblique strategy for honouring someone who rose high from provincial origins. In these final sentences, then, Caerellius quite literally travels from the provinces, hailed by their highest officials, to urbs Roma and the adulation of auditoria sacra, probably the imperial court.Footnote ⁷⁵ In seemingly hyperbolic terms, Censorinus locates his patron in the very nucleus of Roman power, and his attainment of nobility achieves an almost immortal fame. By ending DN 15 with a reference to ‘futura saecula’, he also points directly to the subject of the rest of the book, time.

The encomium highlights a tension inherent to DN: while the text offers Caerellius a kind of immortality through praise (and DN more generally), its structure and themes remind us that everyone who is born will eventually die. In fact, given its overall structure, DN plays with linear and circular conceptualisations of time, here, the arrow-like temporality of a lifetime and the cyclical temporality of cultural memory and (literary) ‘immortality’. The subject of DN 14 drives home the notion of time's linearity by focusing on the human life span.Footnote ⁷⁶ Yet with ‘futura saecula’, Censorinus is indicating that while ‘great’ men may live only a short time, their glory will continue to circulate through words — defying the temporality of a human life. This notion reactivates DN's connection to Horace, Carm. 4.8, which promises, ‘dignum laude uirum Musa uetat mori: / caelo Musa beat’ (‘The Muse keeps the praiseworthy man from death: the Muse blesses him with heaven’).Footnote ⁷⁷ Rome itself participates in this tension: later in DN, Censorinus repeats from Varro's Antiquities an augur's prediction the city will last 1,200 years after its founding (17.15), so a little more than two centuries are left by the time DN was composed.Footnote ⁷⁸ The final envoi of Metamorphoses 15 evokes a similar problem: as long as Rome stands, Ovid's fame will ensure his immortality throughout ‘omnia saecula’ (15.878). But this comes on the heels of Pythagoras’ memorable speech, prophesying Rome's greatness but also, by implication, its own subjection to flux and change.

Caerellius and his extraordinary qualities ostensibly provoked Censorinus to complete his munus. DN 15 compels the reader to consider the man at the heart of the project, while simultaneously signalling a departure from the perspective of form and content. Caerellius himself recedes in the intervening sections, and even when we do encounter him in DN 15, the terms of praise efface his history. Caerellius is both at the text's core and not, he is both its centre and periphery. If we view this contradiction through DN's encyclopaedic features, the text begins to look more and more like a meditation on the limitations of human efforts to describe both nature (as in Aelian's De natura animalium) and natures (for example, the ‘nature’ of power, knowledge or history in Aulus Gellius’ Noctes Atticae or Ampelius’ Liber memorialis). Rome is at the centre of the text, but simultaneously, DN compels the reader to contemplate a diversity of viewpoints and by implication, the vastness of the Empire.

IV TIME AND ITS LIMITS

DN's final chapters on time (16–24) evoke the tension between unity and plurality, between centre and periphery, and especially between what we know and what exists out in nature. Rome and Roman history are also at the heart of these chapters — Censorinus is explicit that his narrative begins with the founding of the city (‘a conditu urbis Romae’, 16.7), and he takes special care to valorise the power of the Julian calendar. Yet the dynamics of what we might call the imperial ‘timescape’ push against this centring impetus. In these chapters we find a commentary on overlapping, nesting cycles, the variability of which, he explains, is multiplied by the Empire's diversity and territorial extent. Censorinus draws a parallel between the multiplicity of calendar years and opinions among philosophers, ‘cum <in> his conditorum uoluntates non minus diuersae sint quam opiniones philosophorum’ (‘since on these points the inclinations of their founders differed no less than the opinions of the philosophers’).Footnote ⁷⁹ The process of locating a birthday in time requires the coordination of many systems and time frames (recall the parapegma as a conceptual tool); at the same time, understanding the contingency and plurality of those systems destabilises the birthday in DN. The deeper Censorinus goes, the more DN raises questions about the variability and inconsistency of available systems and metrics, and what it means to locate a time with accuracy and precision.

The transformative power of Caesar's calendar underlies Censorinus’ conceptualisation of the birthday as an anniversary. In the first century b.c.e., Romans underwent an extraordinary transition in how they thought about time.Footnote ⁸⁰ Before the calendar reform, the year was elastic in length because of the variable insertion of an intercalary month. Nominally seasonal holidays, such as harvest or vintage festivals, did not necessarily coincide with the appropriate season. The reform fixed this problem, as Caesar ‘made the civil year match up with the sun's course’ (DN 20.8), taking care to add an extra day every four years to keep the two cycles in line.Footnote ⁸¹ This shift affected the nature of anniversaries too. Previously, anniversaries derived significance from the particular day on which they occurred, not through their recurrence at precise, fixed intervals, since the year was anywhere from 355 to 378 days.Footnote ⁸² With the introduction of Caesar's calendar, an anniversary also acquired the significance of occurring at an interval of fixed length after its last celebration; in other words, rather than simply the day itself bearing significance, precise, fixed intervals came to characterise anniversaries too.Footnote ⁸³ This notion emerges in DN through Censorinus’ articulation of his goal as elucidating Caerellius’ birthday, and thus his birth (16.1, see above). This ordering is counterintuitive to a modern reader, but what it suggests is that Censorinus sees the birthday as a fixed date from which one can loop back to birth. Knowing Caerellius’ birthday and his age enables the calculation of the number of days between his birthday and birth.

By the time Censorinus presented DN to his patron, the Julian calendar had been in use for nearly three centuries. He reserves pride of place for the Julian calendar as the closest a ‘civil’ device can come to capturing ‘natural’ time (‘ciuilis’, ‘naturalis’).Footnote ⁸⁴ The notion that the best calendar is consistently accurate in its approximation of a natural cycle (in this case, the sun's course and thus seasonal change) is a thoroughly post-Caesarian idea. Indeed, the way the treatise lays out the history of time measurement reveals that the Roman calendar continued to be a locus for the examination of the relationship between ‘nature’ and ‘culture’. Apropos this precise distinction in DN, Feeney argues, ‘the fascination of the interplay between the natural and the constructed underpins much of the Romans’ engagement with the Caesarian calendar, which invited appraisal as the most successful attempt by any society to capture the natural world's rhythms in a human construction. The calendar thus becomes indispensable to Roman thinking on the problem of culture.’Footnote ⁸⁵ Caesar's calendar exercises a profound conceptual power over Censorinus’ perception of time and anniversaries; it also plays a key role in DN's broader (and subtler) exploration of accuracy, the limitations of human metrics to track phenomena in nature and Roman exceptionalism.

While the paths of celestial bodies follow predictable patterns, Censorinus recognises that human perception of time is unstable. Drawing on Varronian categories, he subscribes to a tripartite division of history: (1) ἄδηλον, ‘unclear’, i.e. pre-history, ‘from man's origin to the first flood’; (2) μυθικόν, ‘mythical’, named for the mythical, outlandish things reported from that epoch, ‘following the first flood to the first Olympiad’; (3) ἱστορικόν, ‘historical’, which spans ‘from the first Olympiad to us’ and is so called ‘because events that happened in this period are contained in true histories’ (21.1).Footnote ⁸⁶ Historical time is stable insofar as it is recorded in trustworthy sources, although Censorinus acknowledges they too have their share of inconsistencies. These inconsistencies extend to the measurement of time, based on metrics that have been applied unevenly or are defined in slippery ways.

Spans of time, such as the saeculum (‘age’ or ‘century’), may have varying lengths, a function of the complex interplay of ‘natural’ and ‘civil’ time. Censorinus explains, ‘saecula aut naturalia sunt aut ciuilia’ (‘saecula are either natural or civil’).Footnote ⁸⁷ To clarify what he means, he turns to Varro, attesting to the tradition found in Etruscan ritual texts (17.5), which explain that in each city the ‘natural’ saeculum is the lifespan of the longest-lived individual born on its founding-day. The second saeculum begins on the day of that person's death, lasting until the death of the longest-lived person born on that day, and so on. Within and among cities, then, the ‘natural’ saeculum would be variable in length. Such a definition confounds the categories of ‘civil’ and ‘natural’, insofar as it relies on the existence of a state.

Censorinus further confounds these categories by noting that some Romans consider a ‘natural’ saeculum to be the span of time between the Secular Games (17.7–12). Citing a range of authorities, he emphasises the highly variable number of years between each performance and notes that inconsistencies also exist in the historical records attesting to the celebrations (for example, 17.11 details controversy about the date of the fourth Secular Games, not to speak of the fact that the saeculum was frequently reckoned at 100 years, but redefined under Augustus as 110).Footnote ⁸⁸ Because of all this confusion, he explains, ‘nostri maiores’ (‘our ancestors’) set the ‘civil’ saeculum at 100 years (17.13), an approximation meant to create consistency, not without some basis in the ‘natural’ environment (17.13–14). Even as he defines a ‘historical’ period as one in which events ‘are contained in true histories’, we are reminded that our records can be unstable and flawed, limiting humans’ ability to measure or inscribe time with precision and accuracy.Footnote ⁸⁹

In addition to historical inconsistencies and the complex interplay of natural and civil, metrics also vary according to different experts and cultural contexts. For instance, Censorinus observes that the precise amount of time constituting a solar year is up for debate — whether it is 365 and one-half days, or 365 and one-eighth — and lists eight different authorities with eight different opinions (19.2). He eventually throws up his hands (19.4–5):

As we see here, particularly ‘ancient’ civilisations had years of widely varying lengths. In cultures with such a radically different perception of what constitutes a year, how were birthdays conceived and celebrated?

All these questions come to a head when Censorinus turns to calendars in DN 20, opening with the acknowledgement of their uarietas, with which this paper began: ‘it is easy to recognise how much diversity (uarietas) there is, if anyone should wish to inquire among the peoples of Italy alone, not to speak of foreigners’ (DN 20.1). The cultural diversity within the Empire, then, is reflected in the work's own uarietas — in style, structure and content, as discussed above. While Censorinus makes it clear he will only focus on the Roman calendar, this acknowledgement serves as a reminder that birthdays may be reckoned differently even among proximate towns and cities, not to speak of variable practices in Greece and across Rome's empire. Not only were birthdays celebrated based on different, local conventions, as Censorinus is well aware, but the variety of local calendars means that one's birthday could be celebrated at different times in different places, even within Italy. Calendars are very variable and very political — in other words, they are human.Footnote ⁹⁰

As Censorinus acknowledges this range of cultural traditions, Rome and Roman customs continue to exert a gravitational pull in the narrative. In a sense, this reflects the Julian calendar's own status as a tool for both ‘the assertion of, or allegiance to, Roman political hegemony’ among cities under Rome's influence, who accommodated it (or not) to varying degrees.Footnote ⁹¹ In DN, Caesar's calendar offers an escape hatch from problems raised by other calendrical systems (no doubt those produced by so-called ciuitates rudes). Censorinus explains that Caesar realised the republican calendar's months did not correspond to the lunar cycle, nor did the year to the solar cycle (DN 22.8). Now with a 365-day year, and a leap day inserted in February every four years (20.8–11), the ‘Julian’ year is fitted, as well as possible, to the ‘natural’ solar year.Footnote ⁹² In this regard, a potent symbol of imperial power, centred in Rome, is naturalised — but not quite. The need for a leap day (20.10) means that the civil calendar year is an approximation of the solar year, and the best approximation is still an approximation. In this way, DN both naturalises — and more subtly undermines — Roman exceptionalism. Indeed, Censorinus’ explanation serves as a reminder that any calendar is a human invention, and while the Julian calendar is the best, it is still but one of many useful tools. Furthermore, it cannot be used alone to define Caerellius’ dies natalis. Isolating events in time was a process of synchronising different frames and systems. Caerellius’ birthday exists at the juncture of different cycles, and the way they are measured and understood (and celebrated) is culturally contingent. DN thus portrays the Julian calendar as the ‘best’, but it does not alone suffice to define Caerellius’ dies natalis, given the nature of time-telling.

By turning to Varro's chronology of the period he calls ἱστορικόν, Censorinus performs a feat that has made the text invaluable for later chronographers, including Scaliger. He provides readers with a range of tools to locate Caerellius’ ‘present’, which in turn reveals how regions outside Italy quite literally synchronise with the imperial centre.Footnote ⁹³ Censorinus isolates Caerellius’ birthday in relation to key events and modes of annual reckoning, including the Roman consular year, years since the first Olympiad, the Julian year, Augustan year (and Egyptian equivalent), indigenous Egyptian year (Nabonassar), Philippic year and the years elapsed since the last Egyptian ‘solar canicular’ (i.e., ‘great’) year.Footnote ⁹⁴ Leading to the next chapter on months (DN 22), we learn that, unlike the Julian year, beginning on 1 January, Egyptian years begin on 1 Thoth, which, in the year DN was presented to Caerellius, fell on 25 June, ‘ante diem VII kal. Iul.’ (DN 21.10). 25 June 238 is thus the terminus post quem for the work. As the start of 268 in (Egyptian) Augustan years fell on 29 August, we are also left with a terminus ante quem, so the treatise's dedication — and thus Caerellius’ birthday — can be dated between 25 June and 28 August 238 c.e.Footnote ⁹⁵ The process of synchronisation requires an acknowledgement (or exploration) of cultural differences, an observation that holds true for overarching universal chronology too (as in the case of Eusebius and Jerome).Footnote ⁹⁶

As DN narrows down to months, days and hours, the final three chapters continue to toggle between the plurality of systems for measuring time (for example, among Albans, March has thirty-six days, DN 22.6) and the civil-natural distinction (explicitly evoked again at 22.1, 23.1). The demarcation of a ‘civil day’ involves a choice about which aspects to privilege in the natural transition from light to darkness, and Censorinus compares the natural day, dies (sunrise to sunset, 23.2), to the ways Babylonians, Romans, Umbrians and Athenians reckon the civil day (23.3). Again, this comparison emphasises the diversity of approaches to the problem of marking time. The same is true for his examination of different ways the day is divided into parts (24); hours only emerged in more recent historical time, with the arrival of the sundial and water clock in Rome, the appropriation of Greek scientific technology (23.7). Indeed, hours are absent from the Twelve Tables, he notes (23.8), attesting to how much has changed in Romans’ understanding of time as their city grew and transformed into the capital of a vast global empire, bringing Greek science into their sphere of influence.Footnote ⁹⁷ Human understanding of ‘natural’ time is shaped by imperialism and technological appropriation.Footnote ⁹⁸

These final chapters, then, leave us with an understanding of the variety of tools and measures available for locating Caerellius’ dies natalis — not only the year, month and day, but down to the hour. As Censorinus works to complete his task, he introduces the reader to the plurality of people's strategies for dividing time. Natural and civil grow tangled as he moves along. The superiority of the Julian calendar embodies a form of Roman imperial pre-eminence in the narrative — how Romans, of all peoples, have come closest to capturing the cycles of nature. In this regard, Caesar's calendar exerts its own kind of centring force, both in the unfolding of Censorinus’ narrative, and in the way it binds together the natural and civil. Even this calendar, however, remains one system among many in a world of relational time, in DN it is both exceptional and not — like Rome itself. The text's depiction of the imperial ‘timescape’ creates an opposing, centrifugal force, sending the reader outwards to consider the diversity of approaches and measures in the Empire, revealing a tension — even contradiction — in Censorinus’ configuration of Rome's place in the world.