Sources

Ennius (ca. 175 BC)

The earliest surviving evidence for the tradition of Romulus’ apotheosis is from Ennius’ ‘Annals’.  This work no longer survives, although there are many references to it in other sources that do. 

1. ✴The most explicit of these fragments is cited by Servius (4th century AD), in his commentary on a passage from Virgil’s ‘Aeneid’ (‘ad Aen.’, 6: 763),  cited the following line by Ennius:
   

2. “Ennius: Romulus passes eternity in heaven with the gods who begat him”, (translated by Sander Goldberg and Gesine Manuwald, referenced below, at p. 163, fragment 56). 
   

3. Goldberg and Manuwald  pointed out that Cicero (‘Tusculan Disputations’, 1: 28) also cited this passage from Ennius.
   

4. ✴In similar vein, Cicero (‘On the Republic’, 1: 64) recorded that:
   

5. “... as Ennius says, after the death of a most excellent king, ... [the people] thus speak out:
   

6. ‘O Romulus, Romulus divine, what a guardian of the fatherland the gods created in you! O father, O sire, O bloodline descended from the gods!’”, (translated by Sander Goldberg and Gesine Manuwald, referenced below, at p. 161, fragment 55).
   

7. ✴A passage by Varro (‘On the Latin Language’, 7: 5-6, ca. 45 BC) is sometimes taken to derive from Ennius’ ‘Annals’ and to refer to Romulus’ apotheosis:
   

8. “I shall speak in this book about words which were put down by the poets ... I will begin with this:
   

9. ‘unus erit quem tu tolles in caerula caeli templa’ (there will be one whom you will raise to the azure precincts of the sky)”, (translated by Sander Goldberg and Gesine Manuwald, referenced below, at p. 145, fragment 32).
   

10. Although Varro did not identify the poet who wrote this line, it is generally accepted that it came from Ennius’ ‘Annals’.  Goldberg and Manuwald (see their note 1) argued that this referred to Romulus, and that Ovid drew on it in two passages that I quote below: ‘Metamorphoses’, 14: 814; and ‘Fasti’, 2: 485.
    

The grammarian Nonius Marcellus (4th century AD), who identified the Hora as ‘iuventutis dea’ (goddess of youth), attributed the following line to Book I of the ‘Annals’:

1. “... <and you,> Father Quirinus, I beseech, and Hora Quirini”, (based on the translation by Sander Goldberg and Gesine Manuwald, referenced below, at p. 159, fragment 51).
   

Some scholars argue that this passage suggests that Ennius equated the deified Romulus with Quirinus.  However, others (see, for example, Jacklyn Neel, referenced below, at pp. 114-5) argue that this passage probably described a prayer that Romulus addressed to Quirinus, and that the earliest surviving evidence for the identification of the deified Romulus with Romulus comes with Cicero (below).

Varro (ca. 45 BC)

The relevant passage by Varro is known to us only because it was cited in a much later commentary on a line by the poet Horace (30 BC), who prophesied that:

1. “A barbaric conqueror will tread on [Rome’s] ashes, his horsemen will trample on the city with clattering hooves, and ...  he will scatter in his arrogance the ossa Quirini (bones of Quirinus, the deified Romulus) that are now sheltered from wind and sun”, (‘Epodes’, 16: 10-14, translated by Niall Rudd, referenced below, at p. 307).
   

In his commentary on this passage, Porphyry (3rd century AD) observed that Horace’s prophecy had been formulated:

1. “... as if Romulus [had been buried rather than taken up to] Heaven or dismembered [by his enemies].  In fact Varro [also] states that Romulus had been buried behind the Rostra”, (translated by  Diana Guarisco, referenced below, at p. 14).
   

Varro’s now-lost passage also seems to inform a probably later commentary known as the Pseudo Acronian scholia:

1. “Most people say that Romulus was buried at the Rostra and that, in remembrance of this, there were two lions, just like the ones that we see today on the tombs, and that is because of this that dead men are praised before the Rostra”, (translated by  Diana Guarisco, referenced below, at p. 14).
   

As Jesse Carter (referenced below, at p. 27) observed, Varro might have seen a monument near the republican Rostra before its demolition in the 70s BC.  However, as he also observed, the brief record attributed to him here:

1. “... may be simply the reflection of an aetiological legend that accounted for the custom of holding funeral orations at the Rostra [on the basis of a tradition] that Romulus was buried there.”
   

In other words, this passage certainly suggests that Varro was aware of a tradition in which Romulus was killed by his enemies and buried near the Rostra.

However, Peter Wiseman (referenced below, 2015, at pp. 127-8) argued that Varro would not have endorsed Horace’s identification of the dead Romulus as Quirinus: for Varro:

1. “... , Quirinus was not the deified founder [of Rome] but [rather] one of the Sabine deities introduced to Rome by Titus Tatius.”
   

In this context, he cited the following passage by Varro:

1. “... the ‘Annals’ record that [the Sabine king Titus Tatius] vowed arae (altars) to ... [a number of deities, including] Quirinus ...”, (‘On the Latin Language’, 5: 74, translated by Roland Kent, at p. 71).
   

Another passage indicates that Varro  associated the Temple of Quirinus on the Quirinal with this Sabine deity rather than with the deified Romulus: 

1. “The Quirinal Hill was so named because the fanum (shrine) of Quirinus was there; others say that it is derived from the Quirites, who came with Tatius from Cures to the vicinity of Rome, because they established their camp [on this hill].  This name has caused the names of the adjacent localities to be forgotten.  For, there were other hills with their own names: this is clear from the [archaic sacred itinerary known as the] sacra Argeorum, in which it is written: ‘Quirinal Hill: third shrine, this side of the temple of Quirinus; ...’”, (‘On the Latin Language’, 5: 51-2, translated by Roland Kent, at p. 49).
   

Wiseman cited (at note 16) fragments of lost works by Varro that suggest that he had recorded the deification of Romulus.  However,  he argued that, if so:

1. “... it was evidently under his own name ...”
   

As he pointed out, Varro recorded a temple of Romulus near the Palatine: 

1. “The Palatine ... is so-called because the Pallantes came there with Evander ... The Cermalus must have been  joined to it, ... because, it is written [in the sacra Argeorum]: ‘Germalian: fifth shrine, at the aedes Romuli, ... .’”, (‘On the Latin Language’, 5: 53-4, translated by Roland Kent, at p. 51).
   

Wiseman suggested (at note 17) that this might be at the site otherwise known as the hut of Romulus on the slopes of the Palatine.

Cicero (ca. 45 BC)

Timothy Cornell (referenced below, 1986, at p. 244) observed that:

1. “...  those Romans of Cicero's day  ... who had any sort of education probably obtained their first and most lasting impressions [of their own history] from Ennius' ‘Annals.”
   

This was certainly true of Cicero himself, who observed that:

1. “... our own Ennius  ...  wrote that, in about the 350th year after Rome was founded [i.e. in ca. 400 BC], in the month of June (the day was then the 5th), the moon and night obscured the shining sun.   Based on this date, which was recorded by [both] Ennius and in the ‘Annales Maximi’, the dates of previous eclipses of the sun have been reckoned, all the way back to that which occurred on Nones of Quinctilis [7th July] in the reign of Romulus.  For, even though, during the darkness of that eclipse, Nature carried Romulus away to man's inevitable end, yet the story is that his merit led to his translation to Heaven”, (‘On the Republic’, 1: 16).  
   

Two surviving passages by Cicero constitute our earliest surviving evidence for the tradition that a man called Proculus Julius brought the news of Romulus’ apotheosis to Rome:

1. ✴In an imagined debate with Atticus, Cicero asked his friend whether he accepted:
   

2. “... the ‘fact’ that Romulus, after his death, while wandering about near the place where your house now stands [i.e., on the Quirinal]:
   

3. •met Proculus Julius;
   

4. •told him that he [Romulus] was [now] a god and was called Quirinus; and
   

5. •ordered that a temple be dedicated to him on that spot”, (‘On the Laws’, 1: 3, translate by Clinton Keyes, referenced below, at p. 299).
   

6. ✴He provided more detail in another passage:
   

7. “... such was Romulus’ conspicuous ability that men believed, on the authority of that homini agresti (farmer), Proculus Julius, something that they had not believed about any other mortal for many generations: we are told that this Proculus, at the instigation of the senators (who wanted to free themselves from all suspicion in regard to Romulus' death) stated before a public assembly that he had seen Romulus on the hill now called the Quirinal; and that Romulus had ordered him to ask the people to build him a shrine on that hill, as he was now a god and was called Quirinus”, (‘On the Republic’, 2: 20).
   

The second of the passages above is the earliest surviving evidence of the tradition that, before Proculus Julius reached Rome, many people suspected that the senators had murdered Romulus: Cicero seems here to characterise Proculus’ testimony as a fable invented at their behest in order to allay suspicion.  Two other surviving passages suggest that Cicero was generally sceptical about the deification of mortals: 

1. ✴“Human experience and general custom have allowed men to deify distinguished benefactors ... This is the origin of Hercules, of Castor and Pollux, of Aesculapius ... This is also the origin of Romulus, who is believed by some to be the same as Quirinus.  Since their souls survived and enjoyed eternal life, these benefactors were deemed to be gods, who are both supremely good and immortal”, (‘On the Gods’, 2: 62).
   

2. ✴“...  even in Greece they worship a number of deified mortals ... ; and with our own people, Romulus and many others, who are believed to have been admitted to celestial citizenship in recent times, by a sort of extension of the franchise!  Well, those are the superstitions of the unlearned ...”, (‘On the Gods’, 3: 39).
   

Livy (ca. 25 BC)

Livy is the earliest surviving source for the traditions surrounding the manner of Romulus’ death:

1. “Romulus held a review of his army at the ‘Caprae Palus’ in the Campus Martius.  A violent thunder storm suddenly arose and enveloped  [him] in so dense a cloud that he was quite invisible to the [assembled men].  From that moment, Romulus was no longer seen on earth.  ... [When] bright, calm sunshine [returned] after such fearful weather, .. the royal seat was vacant.  ... The senators who had been standing close to him [asserted] that he had been snatched away to Heaven by a whirlwind ...  At length, ...[all] those present hailed Romulus as a god, the son of a god, and regem parentemque urbis Romana (the king and father of the city of Rome).  They made supplications for his grace and favour, and prayed that he would be propitious to his children [i.e., the Romans] and save and protect them”, (‘History of Rome’, 1: 16: 1-3).
   

This fleshes out the scant information that can be gleaned from Cicero (above), who had Romulus die during an eclipse.  However, Livy was extremely sceptical about this putative apotheosis:

1. “I believe ... that, even at that time, there were some who secretly hinted that [Romulus had actually been torn limb from limb by the senators, presumably under the cover of the violent storm]; a tradition to this effect, although certainly a very dim one, has filtered down to us”, (‘History of Rome’, 1: 16: 4).
   

Livy then recorded that:

1. “... the generally-accepted belief [in the apotheosis of Romulus] was strengthened by one man's clever device: the tradition runs that a man called Proculus Julius, whose authority had weight in matters of even the gravest importance, saw how deeply the community felt the loss of the king, and how incensed they were against the senators [suspected of having killed him]”, (‘History of Rome’, 1: 16: 5). 
   

He therefore appeared before the assembly and reported that, at dawn on that very day:

1. “... the father of this city [i.e., Romulus] suddenly descended from Heaven and appeared to me.  While ... I stood transfixed before him in deepest reverence, praying that I might be pardoned for gazing upon him, he addressed me as follows:
   

2. ‘Go, tell the Romans that it is the will of Heaven that my city of Rome should be the head of all the world.  Let them henceforth cultivate the arts of war: let them know for certain that no human might can withstand the arms of Rome, and let them  hand down this  knowledge to posterity’”, (‘History of Rome’, 1: 16: 7). 
   

Livy dismissed this tale by observing that:

1. “It is marvellous what credit was given to this man's story, and how the grief of the people and the army was soothed by the belief that it created in the immortality of Romulus”, (‘History of Rome’, 1: 16: 8).
   

Dionysius of Halicarnassus  (7 BC)

Dionysius of Halicarnassus made no mention of Proculus Julius in his initial account of the death and apotheosis of Romulus.  In this account, Romulus celebrated three triumphs during his reign, the last of which was over the Etruscan city state of Veii:

1. “His failure to subdue any more of the neighbouring nations seems to have been due to his sudden death, which happened while he was still in the vigour of his age for warlike achievements.  There are many different stories concerning it.
   

2. ✴Those who give a rather fabulous account of his life say that, while he was haranguing his men in the camp, sudden darkness rushed down out of a clear sky and a violent storm burst, after which he was nowhere to be seen; and these writers believe that he was caught up into Heaven by his father, Mars.
   

3. ✴But those who write the more plausible accounts say that he was killed by his own people; and the [main] reason they allege for his murder is that  ... he now seemed to be harsh and arbitrary and to be exercising his power more like a tyrant than a king.  For these reasons, they say, the patricians formed a conspiracy against him and resolved to kill him; and, having carried out the deed in the senate-house [presumably the shrine of Vulcan], they divided his body into several pieces ... and then emerged, each one hiding his part of the body under his robes and afterwards burying it in secret.
   

4. ✴Others say that while haranguing the people [presumably in the Forum], he was slain by the new citizens of Rome, and that they undertook the murder at the time when the rain and the darkness occurred, the assembly of the people being then dispersed and their chief left without his guard.  And for this reason, they say, the day on which this event happened got its name from the flight of the people, and is called Populifugia [a festival celebrated on 5th July], down to our times.
   

5. Be that as it may, the incidents that occurred by the direction of Heaven in connexion with this man's birth and death would seem to give considerable authority to the view of those who make gods of mortal men and place the souls of illustrious persons in Heaven.  For, they say that, at the time when his mother was violated, whether by some man or by a god [i.e., Mars], there was a total eclipse of the sun and a general darkness ... covered the earth, and that at his death the same thing happened.  Such, then, is reported to have been the death of Romulus, who built Rome and was chosen by her citizens as their first king.  He left no issue, and after reigning 37 years, died in the 55th year of his age; for he was very young when he obtained the rule, being no more than 18 years old, as is agreed by all who have written his history”, (‘Roman Antiquities’, 2: 56: 1-7).
   

Dionysius returned to the apotheosis of Romulus in a passage in which he recorded that Numa, the second King of Rome (traditionally 715-672 BC):

1. “... ordered that Romulus himself, as someone who had shown a greatness beyond mortal nature, should be honoured under the name of Quirinus by the erection of a temple and by sacrifices throughout the year.  For, while the Romans had been still in doubt whether divine providence or human treachery had been the cause of his disappearance, a certain farmer named Julius, a descendant of Ascanius, who was of such a blameless life that he would never have told an untruth for his private advantage, arrived in the Forum and said that, as he was coming in from the country, he saw Romulus departing from the city fully armed and that, as he drew near to him, he heard him say these words:
   

2. ‘Julius, announce to the Romans, from me, that the genius to whom I was allotted at my birth is conducting me to the gods, now that I have finished my mortal life, and that I am Quirinus’”, (‘Roman Antiquities’, 2: 56: 1-7).
   

Interestingly, Dionysius identified the ‘Proculus Julius’ of both Cicero and Livy as ‘Julius’ tout court, but explicitly recorded his descent from Ascanius, the son of Aeneas and the first king of Alba.  A passage in the ‘Origo Gentis Romanae’ of ca. 400 AD records that:

1. “... the Latins ... believed that, because of his outstanding courage, Ascanius [must have been] descended from Jupiter ... [Therefore], by slightly changing his name to form a diminutive [of Jove, they], first called him Iolus and afterward Iulus.  From him, the Julian family originated, as Caesar writes in Book II and Cato writes in the ‘Origines’”, (‘OGR’, 15: 5).
   

‘Caesar’ here would have been Lucius Julius Caesar, the consul of 64 BC and author of a work known as the ‘Libri Pontificales’ (who was still alive in 44 BC, when his more famous relative was murdered).  This work is lost, and our knowledge of it derives almost exclusively from fragments of it cited in the ‘OGR’:

1. ✴The last-known of these fragments (‘OGR’, 22: 2) related to the early part of the history of Romulus and Remus; and
   

2. ✴the ‘OGR’ itself (as it survives) ended with the death of Remus.
   

It is therefore entirely possible that Dionysius derived his information about ‘Julius‘ from a later and now-lost passage in the ‘Libri Pontificales‘ of Lucius Julius Caesar. 

Verrius Flaccus (1st century BC/ 1st century AD)

According to Festus (2nd century AD), in his epitome of the now-lost lexicon of M. Verrius Flaccus:

1. “Niger lapis in Comitio locum funestum significat, ut ali, Romuli morti destinatum, sed non usu ob in...”, (‘De verborum significatione’, 184 L, lines 188-9).
   

Timothy Cornell (referenced below, 1995, at p. 419, note 42) translated these lines as follows:

1. “[The black stone in the Comitium] indicates a deathly place, intended for the death of Romulus.”
   

Jesse Benedict Carter (referenced below, at p. 26) observed that, while the rest of this entry, as it survives, is lacunose, lines 191-2 begin (respectively) with the fragments ‘stulum’ and ‘tilium’, which have been reasonably restored as Faustulum and Hostilium, indicating (respectively):

1. ✴the herdsman Faustulus, who had rescued the abandoned Romulus and Remus and raised them as his own; and
   

2. ✴Hostus Hostilius, the grandfather of Tullus Hostilius, traditionally the third king of Rome.
   

Thus, the ‘black stone in the Comitium’, to which Flaccus apparently referred to in the present tense, marked a place that:

1. ✴had been intended ‘for the death of Romulus’ (Romuli morti destinatum); and
   

2. ✴might have had now-unknown association with Faustulus and Hostilius. 
   

This leads us to two passages by Dionysius:

1. ✴During the battle between Romulus and Remus in which the latter was killed:
   

2. “... some say that Faustulus, who had brought up the youths, wishing to put an end to the strife of the brothers and being unable to do so, threw himself unarmed into the midst of the combatants, seeking the speediest death, which fell out accordingly.  Some say also that the stone lion that stood in the principal part of the Forum, near the Rostra. was placed over the body of Faustulus, who was buried by those who found him in the place where he fell”, (‘Roman Antiquities’, 1: 87: 2-3).
   

3. ✴The grandfather of the Tullus Hostilius, had moved from Medullia in Latium to Rome, where he:
   

4. “... married a woman of the Sabine race, the daughter of Hersilius, the same woman who had advised her country-women to go as envoys to their fathers on behalf of their husbands at the time when the Sabines were making war against the Romans, and was regarded as the person chiefly responsible for the alliance then concluded by the leaders of the two nations.  This man, [whom he named simply as Hostilius], after taking part with Romulus in many wars and performing mighty deeds in the battles with the Sabines, died ... and was buried by the kings in the principal part of the Forum and honoured with a monument and an inscription testifying to his valour”, (‘Roman Antiquities’, 3: 1: 2-3).
   

Ovid (8 AD)

‘Metamorphoses’

Ovid described the apotheosis of Romulus in his ‘Metamorphoses’, which he finished in 7 AD:

1. “After Tatius had fallen and you, Romulus, were devising equal laws for both the tribes, Mars put off his gleaming helmet and thus addressed the father of gods and men [i.e. Jupiter] as follows:
   

2. ‘Since the Roman state now stands firm on strong foundations and no longer hangs on the strength of one man alone, the time is come, O Father, to grant the reward that you promised to me and to your worthy grandson [Romulus]: that you would take him from earth and set him in the Heavens.  Once, in full council of the gods, ... you declared that:
   

3. Unus erit quem tu tolles in caerula caeli (there will be one that you will exalt to the blue Heavens, an almost exact rendition of the words of the poets, probably Ennius, given by Varro, above).’
   

4. Now, let the full meaning of your words be ratified. The omnipotent Father nodded his assent; then, hiding all the sky with his dark clouds, he filled the earth with thunder and lightning.  Gradivus [i.e. Mars] knew this for the assured sign of the translation that had been promised him; and, leaning on his spear, dauntless he mounted his chariot drawn by steeds straining beneath the bloody yoke, and swung the loud-resounding lash. Gliding downward through the air, he halted on the summit of the wooded Palatine. There, as Ilia’s son [Romulus] was giving kingly judgment to the Quirites, he caught him up from earth.  His mortal part dissolved into thin air...  And now a fair form clothes him, worthier of the high couches of the gods, a form like that of Quirinus in his trabea (ceremonial toga)”, (‘Metamorphoses’, 14: 806-828, translated by Frank Justus Miller, referenced below, at pp. 357-9). 
   

Ovid then described the apotheosis of Romulus’ widow:

1. “His wife was mourning him as lost, when regal Juno bade Iris go down to Hersilia on her arching way with these directions for the widowed queen:
   

2. ‘O queen, bright glory both of Latium and of the Sabine race, most worthy once to have been the consort of so great a man, and now of divine Quirinus, cease your laments and, if you would indeed behold your husband, come with me to yonder grove which stands green on Quirinus’ hill, shading the temple of the king of Rome.’
   

3. Iris obeyed and, gliding to earth along her rainbow arch, accosted Hersilia in the words which had been given her.  She, scarce lifting her eyes and with modest look, replied:
   

4. ‘O goddess ..., lead, oh, lead me on, and show me my husband’s face.  If only the fates grant me but once to see him, then shall I say I have gained heaven indeed.’
   

5. Straightway, she fared along with [Iris] to the hill of Romulus. There, a star from high heaven came gliding down to earth, and Hersilia, her hair bursting into flame from its light, goes up together with the star into thin air.  Rome’s founder receives her with dear, familiar hands and changes her mortal body and her erstwhile name: he calls her Hora, and now as goddess is she joined once more to her Quirinus”, (‘Metamorphoses’, 14: 829-851, translated by Frank Justus Miller, referenced below, at pp. 359-61).
   

‘Fasti’

Ovid returned to this apotheosis in his entry for 17th February, which was the day of the Quirinalia, which:

1. “... is dedicated to Quirinus, who is so-called (he was Romulus before), perhaps:
   

2. ✴because the ancient Sabines called a spear curis and, by his weapon the warlike god [Romulus] won his place among the stars; or
   

3. ✴because the Quirites, [both Latin and Sabine], gave their own name to their king [Romulus]; or
   

4. ✴because he united [the Sabines of] Cures to Rome.
   

Although Ovid maintained the traditional Sabine etymologies, Quirinus himself is no longer a Sabine deity: he is now the deified form of the Latin/ Roman Romulus”, (‘Fasti’, 2: 475-80, translated by James Frazer, referenced below, at p. 91). 

The rest of this passage was devoted, not to the Quirinalia, but to the apotheosis of Romulus as Quirinus (which occurred in early July, on 5th according to Dionysius or the 7th according to Cicero):

1. “For when the father [Mars], lord of arms, saw the new walls [that Romulus had built on the Palatine] and the many wars that Romulus waged, he cried:
   

2. ‘O Jupiter, the Roman power is strong: it no longer needs the services of my son: give him back to his father.  Though one of my two sons, [Remus], has perished, the one who is left to me will suffice for both.  You, yourself, have promised that: Unus erit quem tu tolles in caerula caeli (there will be one that you will exalt to the blue Heavens).  Let the word of Jupiter be kept.’
   

3. Jupiter nodded assent.  At his nod, both poles [of the earth] shook, and Atlas shifted the burden of the sky.  There is a place which the ancients call the Caprae Palus  (Marsh of the Goat).  It chanced, Romulus, that you were judging your people there.  The sun vanished and rising clouds obscured the Heaven, and there fell a heavy shower of rain in torrents.  Then it thundered, then the sky was riven by shooting flames.  The people fled and [Romulus] soared to the stars on his father’s horse”, (‘Fasti’, 2: 480-96, translated by James Frazer, referenced below, at pp. 91-3). 
   

This section overlaps that account above from the ‘Metamorphoses’, albeit that it concentrated on the events on the ground during the apotheosis while the ‘Metamorphoses’  concentrated on Romuls’ ascent to Heaven.

Ovid then moved to the intervention of Proculus Julius: after Romulus’ disappearance during this dreadful storm:

1. “There was mourning [among the people who had fled from the Caprae Palus ], and the senators were falsely charged with murder ... But, as Proculus Julius was coming [to Rome] from Alba Longa, ... the hedges on his left suddenly shook and trembled. ... It seemed to him that Romulus ...  [appeared to him] and said:
   

2. ‘Forbid the Quirites to mourn, let them not profane my divinity by their tears.  Bid the pious throng to bring incense and propitiate the new Quirinus, and bid them cultivate the arts of their fathers, the arts of war.’
   

3. Having so ordered, Romulus/Quirinus vanished into thin air.  Proculus called the people together and reported the words as he had been bid.  Temples were built to the god, and the hill also was named after him, and the rites observed by our fathers come round on a fixed days”, (‘Fasti’, 2: 496-511, translated by James Frazer, referenced below, at pp. 93-5). 
   

Plutarch (late 1st century AD)

According to Plutarch, when Romulus:

1. “... divided the territory acquired in war [with Veii] among his soldiers and released the Veientine hostages without consulting the patricians, he was thought to be insulting their Senate outright.  Therefore, when Romulus disappeared unaccountably a short time, suspicion and calumny descended upon the Senate.  He disappeared on the Nones [7th] of July, as they now call the month, then Quintilis, leaving no certain account nor even any generally accepted tradition of his death, aside from its date ... For, on that day, many ceremonies are still performed that seem to commemorate  what then came to pass”, (‘Life of Romulus’, 27: 2-3).
   

A later passage makes clear how Plutarch arrived at the putative date of Romulus’ death:

1. “... the day on which [Romulus] vanished is called the Poplifugia [People's Flight] and the Nonae Caprotinae, because the people leave the city and sacrifice at the Caprae Palus [Gooat’s Marsh, in the lowest part of the Campus Martius] ... , shouting out many local names, like Marcus, Lucius, and Caius, in imitation of the way in which, on the day when Romulus disappeared [here], they called upon one another in fear and confusion”, (‘Life of Romulus’, 29: 2).
   

Plutarch’s following remarks make it clear that there were other explanations for these two apparently archaic festivals.  Howard Scullard (referenced below, at p. 162) explained that:

1. “Plutarch confuses the issue by saying that ... the Poplifugia and Nonae Caprotinae [took place on the same day]: ... the calendars show that these [were separate] festivals [that] fell on different days, the 5th and 7th [of July respectively].”
   

In fact, it is unlikely that either of these festivals had anything to do with Romulus.

Having alluded to the mystery surrounding the death of Romulus, Plutarch then set out the main traditions that grew up to explain it:

1. “Romulus disappeared suddenly, and no portion of his body or fragment of his clothing remained to be seen:
   

2. ✴Some conjectured that the senators, convened in the shrine of Vulcan), fell upon and killed him and cut his body in pieces, after which each hid a portion [of the body] in the folds of his robe and so carried it away.
   

3. ✴Others think that he disappeared ... when he was holding an assembly of the people outside the city near the so‑called Goat's Marsh [see above], when ... the light of the sun suddenly failed and night descended upon them ... with awful peals of thunder and furious blasts driving rain ... [At this], the multitude dispersed ...  but the nobles gathered together .  When the storm had ceased and the sun appeared once more, the multitude returned and anxiously searched for their king.  However, the nobles would not allow them to inquire into his disappearance ... but instead exhorted them all to honour and revere Romulus, since he had been caught up into Heaven and was to be a benevolent god for them instead of a good king”, (‘Life of Romulus’, 27: 5-7). 
   

Plutarch then moved to the intervention of Proculus Julius.  Whatever the precise circumstances in which Romulus disappeared, most people apparently believed that he had ascended to Heaven as a god.  However, some were unconvinced and accused the Senate of having murdered him:

1. “At this point, it is said that one of the patricians, a man of noblest birth and of the most reputable character, a trusted and intimate friend of Romulus himself and one of the colonists from Alba, Julius Proculus by name, went into the Forum and solemnly swore by the most sacred emblems before all the people that, as he was travelling on the road[from Alba], he had seen Romulus coming to meet him, fair and stately to the eye as never before, and arrayed in bright and shining armour.  terrified by this apparition, had said:
   

2. ‘O King, ... [why] have have you left us patricians a prey to unjust and wicked accusations, and the whole city eternally grieving the loss of its father?
   

3. Whereupon Romulus replied:
   

4. ‘It was the will of the gods, O Proculus, from whom I came, that I should be with mankind only a short time and that, after founding a city destined to be the greatest on earth for empire and glory, I should dwell again in Heaven.  So farewell, and tell the Romans that, if they practise self-restraint and valour, they will reach the utmost heights of human power.  And I will be your propitious deity, Quirinus.’
   

5. The Romans believed this testimony because of [Proculus’] reputation and the oath that he had taken.  Furthermore, divine inspiration shaped their emotions, so that no-one contradicted Proculus: instead, they all put aside suspicion and calumny, prayed to Quirinus, and honoured him as a god”, (‘Life of Romulus’, 28: 1-3).
   

Suetonius (121 AD) and Cassius Dio (ca. 229 AD)

After the death of the Emperor Augustus in 14 AD, the tradition of Romulus’ apotheosis appears to have been applied to that of Augustus:

1. ✴According to Suetonius:
   

2. “... [Augustus’] eulogy was twice delivered:
   

3. •by Tiberius, in front to the temple of divus Julius; and
   

4. •by Drusus, Tiberius’s son, from the old Rostra.
   

5. [His remains were] carried on the shoulders of senators to the Campus Martius and there cremated. There was even an ex-praetor who took oath that he had seen the form of the Emperor, after he had been reduced to ashes, on its way to Heaven”, (‘Life of Augustus’, 100: 3-4). 
   

6. ✴Cassius Dio named this witness of Augustus putative apotheosis: Augustus’ widow, Livia:
   

7. “... bestowed 1,000,000 sesterces upon a certain Numerius Atticus, a senator and ex-praetor, because he swore that he had seen Augustus ascending to Heaven, in the manner that tradition tells concerning Proculus and Romulus”, (‘Roman History’, 56: 46: 1-2).