One of the most famous allegations made against the emperor Caligula was that he had intended to appoint his favourite horse, Incitatus, as consul.Footnote ¹ While Suetonius and Cassius Dio both preserve this allegation, neither explains the basis for it, what exactly Caligula had said or done to lead those about him to believe that this is what he had intended to do.

For his part, Suetonius includes the allegation immediately after his description of how Caligula had a gladiator called Columbus poisoned, at the end of his list of the emperor's passions verging on madness, and as the climax of his description of Caligula's mad devotion to the green chariot faction to whose stable Incitatus belonged:

In contrast, Dio digresses on the subject of Caligula's treatment of Incitatus while describing the various measures to which he was forced to resort in order to raise funds in a.d. 39. A statement that Caligula used to poison the most famous of the gladiators whom he had sold to those forced to hold public games leads him to record that he also used to do the same to horses and charioteers belonging to rival factions to his favourite green chariot faction, which then leads him to digress on Caligula's enthusiasm for chariot-racing more generally, and his love of Incitatus in particular:

The similarity of their claims concerning the treatment of Incitatus as if he were human combines with their common transition from the subject of Caligula's poisoning of gladiators to his devotion to the green faction in general, and to Incitatus in particular, to suggest that Suetonius and Dio drew upon the same ultimate source for their knowledge of Caligula's treatment of Incitatus.Footnote ⁴ Hence one cannot use the claim in one author to support the same or similar claim in the other.

So what is one to make of the claim that Caligula had planned to appoint Incitatus as consul? Most modern commentators seem inclined to treat it as a misinterpretation of some joke or sarcastic comment that was taken out of context and subjected to a literal interpretation.Footnote ⁵ The problem lies in identifying the nature of the joke. Willrich suggested that Caligula had intended his remark as a sarcastic comment on the qualities of the consuls, something to the effect that so many asses had already reached the consulship that he ought to consider appointing the noble steed Incitatus to this post as well.Footnote ⁶ Barrett claims that ‘many stories were spread about Incitatus, originating most likely from Caligula's own humorous quips’, but does not attempt to explain what he might have said in this instance.Footnote ⁷ Hurley accepts that Caligula's original comment, whatever it was exactly, was a joke, and suggests that it is related to Cassius Chaerea's reply to those soldiers demanding a new emperor after the assassination of Caligula, that he would give them one if someone would bring him a password from the charioteer Eutychus first.Footnote ⁸ However, while Chaerea's comment was undoubtedly intended to remind his men of Caligula's fanatical interest in chariot-racing, to the extent that he had even forced them to work in the construction of new stables, this does not contribute anything to our understanding of Caligula's original comment.

Wardle finds Willrich's explanation of the joke ‘plausible’.Footnote ⁹ Alston interprets the apparent promise to make Incitatus a consul as ‘an insult, calculated and witty, aimed at the senate and their pretensions’, a position that comes perilously close to accepting that he really did intend to appoint Incitatus as consul, since that would have been the greatest insult of all to the Senate.Footnote ¹⁰ Adams accepts that Caligula's comment was ‘perhaps a joke’, but also deadly serious in so far as it was probably intended to remind his listeners of his absolute power, namely that he could have appointed Incitatus as a consul if he had really wanted to.Footnote ¹¹ Finally, Winterling seems to believe that Caligula pretended to appoint Incitatus as consul as the end of a longer process of equipping him with all the other possessions of a typical senatorial household in order to satirize the main aim of most aristocrats' lives.Footnote ¹² The problem with this interpretation, however, is that this would have been a dull, drawn-out joke, lacking in the biting wit which was more characteristic of Caligula's sense of humour. Furthermore, it is arguable that such behaviour would have seemed to mock the office of consul as much as the pretensions of those who competed so eagerly for it, and Caligula's repeated tenure of this office in a.d. 37, 39, 40, and 41 suggests that it is unlikely that he would have wished to do this.

The purpose of this note is to propose a new explanation for the origin of the belief that Caligula had wanted to make Incitatus a consul. Given the subject matter of the apparent joke – if that is what it was – it seems reasonable to assume that it was some controversy concerning the appointment, or proposed appointment, of a consul that provoked Caligula to say what he did. Furthermore, given the nature of his sense of humour, or, indeed, of the Roman sense of humour more generally, which enjoyed puns or other wordplay upon real names, it seems not unreasonable to focus on the possibility that his remarks may have concealed some play upon the name of a proposed appointee as consul.Footnote ¹³ Unfortunately, it is impossible to know who canvassed unsuccessfully for appointment to the consulship, so one is forced to focus on the successful candidates alone. On the brighter side, however, there are relatively few gaps in the consular fasti for the reign of Caligula.Footnote ¹⁴ The names of all the consuls, both ordinary and suffect, are known for a.d. 37 and 38; the name of only one suffect consul remains missing for a.d. 39, while those of the last two pairs of suffect consuls for a.d. 40 are also missing. As far as wordplay is concerned, probably the two most relevant factors here are that Incitatus was a horse (equus), and that his name derived from the adjective incitatus meaning ‘fast-moving, rapid, rushing’.Footnote ¹⁵ Hence what one is searching for here is the possession by a consul of a name that leant itself to some witty play upon either the noun equus or the adjective incitatus.

The names of those appointed as ordinary consuls provide the obvious starting point. These were M. Aquila Iulianus and P. Nonius Asprenas for a.d. 38, Caligula himself and L. Apronius Caesianus for a.d. 39, Caligula without colleague for a.d. 40 (since his proposed colleague had died without replacement just before he was due to take office), and Caligula and Cn. Sentius Saturninus for a.d. 41.Footnote ¹⁶ Within this list, the name of Aquila (‘eagle’) seems to provide potential for some sort of humorous comparison between the relative merits of an eagle or a horse for the office of consul, but no obvious witticism suggests itself. Similarly, the name Apronius seems to provide the basis for some sort of comparison between the relative merits of a boar (aper) and a horse, but no obvious witticism comes to mind in this case either. Hence one needs to turn to the names of the suffect consuls. In this case, one's attention is immediately drawn to two appointments in particular, that of the emperor's uncle Ti. Claudius Nero Germanicus as suffect consul for two months beginning 1 July a.d. 37, and that of Ser. Asinius Celer as suffect consul for six months beginning 1 July a.d. 38.Footnote ¹⁷

The appointment of Claudius as suffect consul warrants attention here for two reasons, the first being the meaning of the nomen gentilicium Claudius itself, the second being the fact that it must have been a controversial appointment. On the first point, the name Claudius derives from the adjective claudus meaning ‘lame, halting’.Footnote ¹⁸ Hence there was clear potential for some form of witty opposition between his name and that of Incitatus, ‘fast-moving’. It is possible, therefore, that the origin of the belief that Caligula had wanted to appoint his horse Incitatus as consul may lie in the misinterpretation of a remark playing upon the opposition between the names of Claudius and Incitatus. Perhaps Caligula sought to defend his appointment of Claudius as consul by deliberately misinterpreting the objections of those who queried this appointment, as if they were objecting to him on account of his name rather than of his physical or mental handicaps. One may envisage a rhetorical question asking them whether they wanted him to appoint a ‘fast-moving’ rather than a ‘lame’ consul, where it is they who are made to look foolish by seeming to want him to appoint the horse Incitatus as consul rather than Claudius. As to the second point, Claudius suffered from some form of physical and mental handicap from birth, which left him with a variety of problems including weak legs, a nervous tic, forgetfulness, and a stammer, to the point that even his mother is said to have described him as ‘a monster of a man, not finished, but merely begun by Nature’.Footnote ¹⁹ As a result, neither Augustus nor Tiberius had considered him fit for public office. Hence, the fact that Caligula suddenly appointed him to the highest magistracy must have aroused some controversy, perhaps even provoking Caligula to his defence as just suggested.

There is an alternative possibility, however, since the appointment of Asinius Celer as suffect consul draws attention for two reasons also, the first being that his nomen gentilicium, Asinius, derives from the noun asinus (‘ass’), and the second that his cognomen, Celer, derives from the adjective celer (‘swift’).Footnote ²⁰ Hence the name Asinius Celer is easily misrepresented to mean ‘swift ass’. The potential for witty plays between the names of the ‘swift ass’ Asinius Celer and that of the ‘fast-moving’ horse Incitatus is obvious. It is equally possible, therefore, that the origin of the belief that Caligula had wanted to appoint his horse Incitatus as consul may lie in the misinterpretation of some remark playing upon the similarity between the names of Asinius Celer and that of Incitatus. Perhaps Caligula criticized the candidacy of Celer for the suffect consulship by claiming that it would be better to appoint a ‘swift’, prize-winning horse to the post than a mere ‘ass’, no matter how ‘swift’ this ‘ass’. Indeed, bearing in mind that Celer's grandfather, C. Asinius Pollio, had been ordinary consul in 40 b.c., that his father, C. Asinius Gallus, had been ordinary consul in 8 b.c., and that his brothers C. Asinius Pollio and M. Asinius Agrippa had held the same office in a.d. 23 and a.d. 25 respectively, he may even have made a joke much as suggested by Willrich, something to the effect that too many ‘asses’ had been appointed to this post already, so that it was now time for a horse. The possibilities are numerous.

The question, therefore, is whose appointment as suffect consul is more likely to have driven Caligula to joke about making Incitatus consul in the way that he seems to have done. As far as the appointment of Claudius is concerned, one may doubt whether anyone would have dared openly to criticize his candidacy, at least not to Caligula himself. There may have been some whisperings behind the emperor's back, but probably nothing more than this. After all, it was customary for the emperor to choose the consuls by this point, and not unexpected that he should have decided to prefer his nearest living male relative.Footnote ²¹ Furthermore, this was all part of Caligula's very public display of pietas at the start of his reign designed to contrast his behaviour to that of Tiberius previously, even if his attitude towards Claudius would significantly deteriorate subsequently.Footnote ²² However, it is much easier to understand why he might have been driven to mock the candidacy of Asinius Celer for the consulship. It is not hard to see why he might have disapproved of a man whose main claim to fame subsequently was that he paid an excessive price of up to 8,000 sesterces for a red mullet during Caligula's reign, so revealing both great wealth and a desire for public attention, neither of which would have endeared him to the emperor.Footnote ²³ Furthermore, he was a potential rival in that his father's name had been bandied about as a potential successor to Augustus himself during his last days, and he too could pose as a victim of the cruelty of Tiberius, who had starved his father to death in much the same way that he had starved Caligula's brother Drusus to death also.Footnote ²⁴

A key point here is that sometime during his early reign Caligula made a point of restoring the election of magistrates to the assemblies of the people.Footnote ²⁵ It is not quite clear what this meant in practice, except that the emperor no longer controlled the process as tightly as he had done by the end of the reign of Tiberius.Footnote ²⁶ As it happens, this reform does not seem to have worked quite as well as Caligula had hoped, so that he reversed it in September a.d. 39, when he removed the consuls then in office to replace them with his own candidates instead.Footnote ²⁷ Hence Asinius Celer was appointed as consul precisely during the period when Caligula was allowing the Senate and people a much greater role in the election of magistrates than they had enjoyed in recent years. This context explains why Caligula might have been driven to mock a candidate for office, but not then block him from this office, because he still wanted to give his reform a chance to work. However, it is arguable that his exasperation with the choice of Asinius Celer as candidate marked his increasing disappointment with his reform, resulting finally in his abrupt reversal of it in September a.d. 39. On the balance of probabilities, therefore, it is easier to understand why Caligula might have been prompted to joke about appointing Incitatus as consul in the context of the candidacy of Asinius Celer rather than that of Claudius.

A final point is necessary. Dio records that Caligula appointed a horse as a priest of his cult, and it is normally assumed that this horse is identifiable as Incitatus.Footnote ²⁸ It is tempting, therefore, to use this apparent appointment of Incitatus as priest as proof of the high regard in which Caligula held him, and evidence that he may have intended to appoint him consul also, exactly as Suetonius and Dio report. However, this was not necessarily the case. Appointment as a priest in Caligula's cult was a very expensive burden, so that Claudius had been forced to pay eight million sesterces for it, and had had to borrow heavily to do this.Footnote ²⁹ The richest men in Rome also competed for the privilege of this priesthood, although one may suspect a degree of compulsion in many cases, as this seems to have been simply another way for Caligula to raise money.Footnote ³⁰ One possibility, therefore, is that Incitatus may have fallen out of favour, and that Caligula appointed him as his priest as a humorous pseudo-legal means by which to recover the expensive gifts which he had previously lavished upon him. After all, the champion horse in a.d. 37 may have begun to slow by a.d. 40, and the imperial affection to wane accordingly. However, Caligula's sense of humour was usually more pointed than this, and one may suspect a more specific target. It seems more likely, therefore, that he appointed Incitatus as a priest in mockery of someone who had already paid, or been forced to pay, heavily for this privilege. In light of the above, the obvious target is Asinius Celer once more, in continuation of Caligula's earlier joke.