From the first century a.d. to the late third there existed a group of soldiers known as the frumentarii. Centralized in the late first century, they became an increasingly important force throughout the second century until Diocletian abolished them at the end of the third. Modern scholarship has usually seen their purpose as encompassing three roles: couriers, military police and secret police, with the last attracting the most attention.
The frumentarii have long been regarded as the ‘Roman secret service’ and are often compared explicitly to more modern repressive police forces like the Gestapo.Footnote 1 They have been glossed as ‘secret agents’, ‘secret police’, ‘spies’ and an ‘internal security agency’, among other unsavoury descriptions.Footnote 2 Most works acknowledge their other duties, but they are often disregarded: ‘As is well known, [their other duties were] merely a cover for their operations in intelligence gathering and secret police work.’Footnote 3 They are seen as the emperor's eyes and ears; agents who could travel through the Empire at will and spy on the governors and officials who ran the Roman state. This view of the frumentarii is often reproduced in modern fiction as well, and if the public is aware of this unit at all it will most likely be in the guise of the undercover spies, assassins and imperial agents of popular novels such as Harry Sidebottom's Warrior of Rome series.Footnote 4
Yet, the ancient evidence for this role in particular has been overinterpreted and relies heavily on late sources and several questionable assumptions. Indeed, only their duties as military police can be said to be based firmly on the evidence of contemporaries. This article, however, will argue that the key to any understanding of the frumentarii lies in an often overlooked aspect of their duties which goes back to their origins: their service as supply agents. By re-emphasizing this aspect of their duties, it is possible to see how the other roles associated with them evolved as logical extensions of their core duty.
There is little argument among modern historians that the frumentarii were originally tied to supplies.Footnote 5 This can be seen from their very name: frumentarius comes from the Latin word for grain (frumentum). Reynolds's comment that ‘one does not raise a force of King's Messengers and detectives and call them “Purveyors of corn”’ is entirely correct.Footnote 6 They must have originated in such a position before evolving into the more developed form we see later. Their name is, unfortunately, the main evidence we have for what these supply connections were. The firmest additional piece of evidence comes from a surviving Ostian inscription from 17 September a.d. 210, which shows a centurio frumentarius erecting a dedication to the praefectus annonae, the official in charge of Rome's grain supply.Footnote 7 This firmly ties the frumentarii to the supply of the annona ciuica.
Connections to army supply are harder to identify. They do appear in several inscriptions throughout the Empire as frumentarii of various legions, but their exact duties are not specified. Only in Tacitus can we possibly see them serving in this role, as he refers to frumentatores who were sent from an army camp to Novaesium in search of grain during the revolt of Civilis in a.d. 69 (Tac. Hist. 4.35.1). Even this is not unambiguously a reference to the frumentarii, since it is unclear whether he is using a technical term or simply describing their duties as grain-collectors. They may just be an ad hoc group pulled together for the current crisis.
1. THE EVIDENCE
Before examining the role of the frumentarii, it is worth considering the evidence we have for their three most commonly recognized duties. It will then be possible to see how these roles could have evolved out of the original function of the frumentarii, without superseding it.
There are three main sources of information for the frumentarii: Latin literary sources from the fourth century (more than half a century after the unit was disbanded), Greek sources from the third century (which have terminological issues) and epigraphic material (which assumes a basic level of shared knowledge). All of these sources are unsatisfactory in one way or another, but many have been relied on to provide conclusions beyond what they can support. Many of the broader conclusions made from this evidence are stated as fact when they are merely suppositions.
1.1 ‘Secret service’
The modern impression of the frumentarii as a secret police force of spies and assassins is largely derived from the Latin literary sources of the fourth century, all of which (apart from Jerome) have a strongly negative view of the now disbanded unit. Aurelius Victor is the earliest literary source to mention the frumentarii by name, and he wrote his work at least sixty years after the unit was disbanded. Aurelius Victor provides the only explicit statement regarding the purpose behind their creation and is worth citing in full (Aur. Vict. Caes. 39.44–5, transl. Bird [n. 2]):
qui cum ad explorandum annuntiandumque, ecqui forte in prouinciis motus exsisterent, instituti uiderentur, compositis nefarie criminationibus, iniecto passim metu, praecipue remotissimo cuique, cuncta foede diripiebant.
Although they appeared to have been established to investigate and report whatever disturbances might crop up in the provinces, by outrageously fabricating charges and inspiring fear everywhere, especially in all the most remote areas, they would shamefully plunder everything.
While there is little reason to question his account of their reputation in his day, his description of their duties is vague and the rationale he gives for their creation seems to reflect more the reputation that grew up around them than their presumed origins as supply agents.
Another fourth-century work, the Historia Augusta, provides us with our most detailed accounts of frumentarii in action. As with Aurelius Victor this source mainly mentions them as spies with a focus on internal espionage. According to this work, Hadrian had them read his friends’ correspondence, Macrinus used them to investigate the behaviour of his soldiers and Gallienus had them spying on the future usurper Claudius Gothicus.Footnote 8 This material seems to confirm and expand on Victor's testimony. Given this wealth of detail, it is especially unfortunate that the Historia Augusta is so unreliable as well as late.Footnote 9 While some of this information about the frumentarii may reflect the truth, it is difficult to identify where the author is relying on now-lost sources and when he is simply inventing plausible lies.
There are earlier sources that are generally seen as alluding to frumentarii, but terminological issues arise. While Greek inscriptions and the late source John Lydus transliterate the term as φρουμεντάριοι, contemporary Greek historians avoided such vulgarizations. Instead, we see the increased appearance of couriers (ἀγγελιαφόροι and γραμματοφόροι) during the third century in roles that seem more connected with espionage than with messengers. Because of this the terms are generally thought to refer to frumentarii.Footnote 10 Of the three people that Cassius Dio describes as head of the couriers (princeps peregrinorum?) one pair is described as being ‘of great assistance to [Caracalla] in satisfying his unholy curiosity’,Footnote 11 while the third had served as a centurion among the spies and scouts (διόπται καὶ ἐρευνηταί) before promotion to the post (Dio Cass. 79.15.1, 79.14.1–4).
Of course, spying is only a part of what is meant when historians speak of a ‘secret service’. There are also records of frumentarii involved in assassinations of usurpers and dangerously independent officials. Herodian claims that Severus used couriers (frumentarii?) for this purpose against Clodius Albinus and the Historia Augusta features at least one example of this under Commodus (Hdn. 3.5.4–5; SHA Comm. 4.5). A more interesting example is the centurion called Aquilius sent by Didius Julianus to assassinate Severus, described as a specialist in assassinations, particularly of senators or generals (SHA Did. Iul. 5.8, Pesc. Nig. 2.6). The Historia Augusta does not identify him as a frumentarius, but an inscription found at Antium records a certain Aquilius Felix who was active as a centurio frumentarius before being promoted to a procuratorship and then praefectus classis prouinciae Rauennatis.Footnote 12 It is highly tempting to see this as the same man, who received his sudden promotion by switching to the winning side. The fact that the writer of the Historia Augusta was apparently unaware of this makes it compelling evidence for the role of frumentarii as assassins, even if it must currently remain speculation.
While the evidence for this role may seem reasonably extensive, it is clear that all of these sources have serious deficiencies. It is not clear how informed the late Latin writers were, and it is possible that the Greek sources may not even be referring to the unit at all. Even placing these problems to one side, there are several objections to viewing them as an organized secret service as is often assumed. For one thing, there is no indication that they kept their identity as frumentarii a secret, surely an obvious necessity for such a group.Footnote 13 Why would rebels or usurpers allow imperial agents near them if they knew that they were trained spies and assassins who owed allegiance to the emperor?
Instead of a centralized spy bureau, recent studies have emphasized the frumentarii’s dispersed nature and connection to their home provinces. While the frumentarii were centralized to a degree as part of a single numerus quartered in the castra peregrina in Rome, the members of this unit were not in a position to be hand-picked by the emperor or his top officials.Footnote 14 They came from too wide an area for this to be the case. There are frumentarii known from legions all over the Empire, with no apparent preference given to Italians or favourites from other loyal regions. In fact, there are no frumentarii at all recorded from II Parthica, the legion stationed just outside Rome.Footnote 15 This does not suggest a unit whose members were all hand-picked agents of the emperor. Instead, what it suggests is that they were selected for their posts by the governors themselves. If internal intelligence was their primary purpose it would be odd to rely on the governors to choose the spies informing on themselves.
Being a frumentarius does not seem to have been a lifetime post either. A true secret service would want to encourage a career in the centre lest its agents should be tempted to serve more rewarding masters. Instead, there seems to have been no fixed career path for a frumentarius. It was a prestigious role whose holders had good prospects once they left, but they could follow their service as frumentarii by promotion within the regular legions, through the castra peregrina, or through the officium of the governor.Footnote 16 If they truly represented a secret service, there could be nothing more dangerous than letting the governors they were expected to report on control one of their avenues of promotion.
Frumentarii are not even unique as a military unit with connections to spying. The use of soldiers to inform on their commander does not seem to have been uncommon. In his panegyric to Trajan, Pliny the Younger mentions that now ‘no commander need fear being liked or disliked by their soldiers’.Footnote 17 That an emperor might fear a popular general seems obvious, but the only reason for a commander to fear an imperial response (rather than an immediate mutinous one) to his unpopularity with the men would be if it meant soldiers could be expected to inform on him. As highly mobile soldiers, frumentarii could be expected to have more opportunities to sell out their commanders than other soldiers, but this does not make it their primary purpose.
None of this is to deny that the sources show frumentarii in espionage roles, but what we see is less an organized secret police force and more a series of individuals recruited for exceptional duties in exceptional circumstances. Even in the literary sources, this unit's primary purpose was never to ferret out information. Their value as imperial agents came from their other duties and their connections to the provinces.
1.2 Couriers
The use of frumentarii as couriers is more clearly documented in the sources. Aurelius Victor, Jerome and John Lydus call them the predecessors to the agentes in rebus (a later courier unit with a dubious reputation), and the Historia Augusta shows them serving as couriers on several occasions.Footnote 18 Herodian mentions Pupienus sending messengers condemning Maximinus Thrax to all provinces, and the Historia Augusta identifies these as frumentarii.Footnote 19 A frumentarius called Didymus features in an Anatolian inscription delivering Philip's response to a petition.Footnote 20 They can also be seen manning stationes of the cursus publicus, the main communications network of the Empire.Footnote 21 All these facts point to a unit with message-carrying duties.Footnote 22
As with the espionage duties the frumentarii were not the only courier unit or even the only unit of military couriers. It was common practice to send soldiers out to deliver messages, regardless of what unit they came from. If there was a unit that specialized in messenger duty during the first century, it was the speculatores and singulares who served as imperial bodyguards.Footnote 23 This did not make communication duties their primary purpose, and the same probably applies to the frumentarii who seem to have succeeded them as favoured choices for couriers in the second and third centuries.
Like the agentes in rebus to whom Victor compared them, the frumentarii seem to have been used for ensuring secure imperial communication to the provinces. Unlike the agentes the frumentarii appear to have specialized in the regions they were responsible for. They had strong connections with both the centre and the provinces. While having frumentarii serve outside their home provinces was not unheard of, the connection between individual frumentarii and their legions strongly suggests that frumentarii were only expected to carry communications between the centre and their own province. Otherwise why have so many different legions represented? This may have provided a more personalized service, with frumentarii intimately familiar with the officials at both ends of the line of communication they provided. It would, however, have made efforts at centralization difficult. Whereas each agens was of value anywhere in the Empire, frumentarii were only useful for their home province.
1.3 Military police
The frumentarii’s service as military police is not even hinted at in the literary sources and instead appears entirely in epigraphic evidence. Inscriptions from Anatolia see them arresting villagers and confiscating their goods.Footnote 24 We also see them serving on the stationes alongside other military police units such as speculatores, beneficarii, stationarii, etc.Footnote 25 Inscriptions of frumentarii have been found connected to mines in such separate areas as Italy, Raetia and Egypt, where they were presumably overseeing the guards or as administrators.Footnote 26 The frumentarii were too important to have served merely as guards, so they probably had a broader administrative function as well.
Coming as it does from the accounts of people who had actually interacted with frumentarii, these sources have to be considered more reliable than the literary sources. That said, the third century saw a serious increase in the number of soldiers on policing duties, which means that the presence of frumentarii engaged in military policing is not surprising.Footnote 27 Their actual duties remain vague.
2. RECONCILING THE EVIDENCE
These three roles seem to be completely different from the duties associated with supply agents, yet the original connection to that position seems clear. How can supply agents have taken on such disparate duties? It is this very incompatibility that makes re-evaluation of their role so useful. Any explanation for the behaviour of the frumentarii which does not take into account the way in which it evolved out of their regular duties creates four positions that cannot be reconciled.
Fortunately, it is possible to recognize a strand of continuity within these duties. There is a clear connection between the frumentarii’s service as supply officers and their service as couriers. Supply officials would be required to have close contact with the governors, since they had, as commanders of the army, the ultimate responsibility for ensuring that the soldiers were fed. Given this connection it is unsurprising that frumentarii would acquire a position on their officium.Footnote 28 As their duties required them to travel constantly, their use as couriers was not so much an independent function as it was a matter of convenience, since the sender would not have to dispatch two separate soldiers when one was travelling to the recipient anyway.
On the face of it, the use of supply agents as spies seems an unusual choice. Yet, the most valuable spies are the ones who have a reason to travel to the place where information is needed and who are familiar with the figures and the area involved. The duties of supply agent required that they travel throughout the Empire and have access to officials and places which would otherwise be inaccessible.
While their supply duties may have made them somewhat useful as the emperors’ eyes and ears, it was primarily their courier duties that gave them opportunities for such roles. If the emperor wanted information about a distant official (or, indeed, if he wanted him assassinated) the first place to turn would be to the couriers who were his connection to him. Many of the duties that historians recognize as espionage service are in fact very close to the duties of couriers. Hadrian's spying on his friends, for example, was said to have been done through reading their correspondence (SHA Hadr. 11.4–6). Any individual could be used as a spy, but few could compete with the couriers’ ability to go wherever they were wanted. It would have been extremely odd if the central administration did not seek information about the provinces from these officials when they were in Rome on messenger duty, just as it would be if the governors did not ask about conditions in Rome.
The connection to military policing is more difficult to understand. On the face of it, this seems an unusual use for either supply agents or couriers. What need did supply agents have to make arrests and maintain public order? The answer to that question lies in the nature of the frumentarii’s supply duties. To understand why military policing duties were a necessary part of their role it is essential to understand just what that initial role was.
The frumentarii’s role in supply is not well understood. It is generally assumed that they were supplying their legions, but does this mean that they were in charge of transporting supplies from pre-filled granaries, purchasing the grain at market, or distributing it to the soldiers? These are all very different duties. Even the basic connection to army supply has been questioned. Roberto Paribeni suggested that the frumentarii were actually responsible for supply not of the legions but of the imperial court.Footnote 29 While this idea is now generally seen as discredited, it shows that alternate explanations are possible.
A more viable theory was proposed by Geoffrey Rickman, who suggested that they were in fact supervising the transport of the annona ciuica being shipped to Rome. There are several reasons to make this connection. First, the connection to the annona ciuica would explain one of the great mysteries of the frumentarii: why they were in Rome frequently enough to be given permanent quarters and become centralized. There seem to be too many frumentarii in Rome for just the distribution of grain for the military. An official created to oversee the supply of the army might go to Rome occasionally to oversee the purchase and transport of supplies if he was from a local province or in times of emergency, but generally the legions were supplied through the grain raised in tax from their own province or from neighbouring provinces.Footnote 30
It would also explain why supply officials would be given military policing duties. When transporting annona ciuica grain to Rome there would be a need for soldiers as guards and possibly to oversee the operation. Soldiers detached for such duties would keep in constant contact with the city and could easily require their own headquarters there.Footnote 31 Certainly the Ostian dedication to the praefectus annonae does indicate that they had some connection to it.
This argument has the benefit of explaining why the frumentarii became a military policing unit and why they needed a permanent base in Rome, but it has problems of its own. While many of the references to frumentarii come from Rome or Egypt (the main source for Rome's supply), there are a significant number which come from smaller and more isolated provinces, where transportation to Rome would be prohibitively expensive. Why would soldiers responsible for guarding the annona for Rome be needed in regions too far from the city to ever be a suitable source of supplies? For all the elegance of this theory it must be regarded as not providing a fully satisfactory answer.
To understand the supply duties of the frumentarii and their connection to military policing we must look at an example of them in action. The best recorded account of their military policing duties comes from a series of inscriptions found in Lydia. In the area surrounding the ancient city of Philadelphia (modern Alaşehir) there are five separate inscribed petitions, probably dating from the reign of Philip the Arab (244–249), that describe the depredations of soldiers operating in the area.Footnote 32 These petitions describe how groups of soldiers are wandering the countryside demanding services and unjustly arresting villagers for monetary gain. The prime culprits were a unit known as the kolletiones, but they all mention frumentarii along with occasional references to other military units such as stationarii and praetoriani.Footnote 33
It is clear that these soldiers represented a disruptive influence to the villagers. What is less clear is what they were doing there. The two complaints being made against them are that they were arresting villagers without cause and demanding undue services from the towns. There has been a tendency to view the former as the explanation for their presence. In this view they were in the villages as military police keeping order and arresting elements they saw as disruptive or potentially profitable.Footnote 34
This is certainly true to an extent. It is clear from these inscriptions that the main powers being abused are the policing ones that gave these soldiers the right to arrest residents and confiscate goods. While missing the description of their chief crime, the inscription from the village of Ağabey Köyü states that ‘to leave an impression that such an outrage was justified, they [arrested] nine, put them in chains and asserted that they were [sending] them [under escort] to your procurators of equestrian rank’.Footnote 35 These are clearly actions of military policing.
What the conventional explanation does not answer is the question of why they were present at these villages in the first place. These were not major population centres, although they were located along the main road. If they had been visited owing to banditry or similar law-enforcement issues, it seems strange that the petitions would be entirely devoid of denials or defensive justifications. Emperors could be expected to take a dim view of criticism that their soldiers were arresting bandits, and yet the petitions were apparently all successful or else they would not have been inscribed at all.
The other complaint seems of far more use as an explanation for their presence. The villagers of Kassar complain that the village, ‘being (financially) exhausted by its unlimited expenditure on those who stay here and the mass of the kolletiones, is, because of its penury, [bereft] of bath and even bereft of the necessities of life’.Footnote 36 This part of the complaint is clear at least. The villagers are upset because they have to sustain the cost of having the soldiers living in or near their village as part of the requisitions known as angaria (ἀγγαρεία). It has a long history of abuse and appears in several other Anatolian petitions.
Not all complaints of financial exactions can be dismissed in this way though. Ağabey Köyü is again the most explicit, when it complains of ‘the harassment of us performed by the kolletiones and those who on the pretext of offices (ἀρχαί) and liturgies (λειτουργίαι) harass and trouble your peasants’.Footnote 37 This sounds like more than simply the exactions necessary for angaria. A liturgy was the equivalent of the Latin munus, which was a compulsory office placed on individuals to provide services for the state.Footnote 38 It is possible that this refers to local figures being given responsibility for the maintenance of soldiers, but the reference to both ἀρχαί and λειτουργίαι (the two ranks of municipal office) suggests that we are seeing exactions on a larger scale and for a larger purpose. One of the most important activities undertaken by liturgists was the collection of taxes, and it certainly would not be out of keeping for the complaints to be taxation-related as they are decidedly economic in nature.
When looking at the role that the frumentarii played here, it is also important to consider the nature of the kolletiones. The word itself seems to be Latin in origin, being derived from the Latin word collectio (a collecting together) or collatio (a contribution or collection).Footnote 39 Either one would suggest duties tied to taxation, and indeed collationes were the name of a later tax. One group with a name connected to the collection of goods involved in a rural dispute might be a coincidence, but it seems highly unlikely that two separate groups with such names were given tasks as peacekeepers and policemen in a way unrelated to their original duties.
It is clear that, while the kolletiones were new to the task, the frumentarii were the more customary figures. Frumentarii are mentioned twice in ways that imply a more familiar connection to them. The villagers of Kemaliye request that ‘whatever the laws were issued for the frumentarii or similar orders—[we beg you] to command and dispose by some law that the provincial governor shall visit their insolence upon them’.Footnote 40 The villagers not only regarded the frumentarii as the ubiquitous officials for such duties, they also believed that they were mentioned as such in law.
The village of Kavacık is more interesting if not quite as informative. It too is full of complaints about the kolletiones but seems to hold up the frumentarii and praetoriani as exemplars of proper behaviour.Footnote 41 The inscription is too damaged to say more with certainty, but it seems clear that the frumentarii had been performing similar duties to the kolletiones for quite some time by this point. While the actions undertaken are connected to those of military police, such familiarity from the villagers makes it more likely that they were not there for peacekeeping activities (surely these villages were not all bandit hideouts?) but are being recorded performing one of their main functions and seeing to it that supplies were being raised. Their military policing powers are being used in support of this.
So where does that leave the frumentarii’s supply role? If the frumentarii were involved at the level of supply-raising, then the distinction between civil and military supplies becomes less relevant. Army units were initially supplied from the taxes raised by the provinces and the grain destined for the army specifically would only be separated once it reached its destination.Footnote 42 As such, soldiers involved with the collection of supplies for their unit would need to become involved with the provincial tax system as a whole. The gradual expansion of their duties is a sign that this is what happened.
It follows that there is quite a significant overlap between these sorts of supply duties and military policing. In fact, Mitchell views military policing as being designed primarily to compel villagers to pay their taxes.Footnote 43 If this is so, it would then be natural for the soldiers responsible for supplies to assume enforcement duties as well.
It is possible now to make a loose reconstruction of the development of these powers. The frumentarii began by collecting supplies for the legions. They were involved in raising these supplies at a local level, which meant that they often needed to supervise the regular taxes in kind. This would have required enforcing liturgies as needed. This enforcement led to more general military policing duties. Presumably some of the grain raised would have become a part of the annona ciuica (at least in key provinces), and it would be only natural to use the same soldiers who had enforced its collection to oversee its shipment. The frumentarii serving in Rome would not be needed for collection of taxes, as Italy paid no land tax until the time of Diocletian, which is why we only see them there with escort duties and construction works instead of supply raising.
Rather than declining, it seems likely that the frumentarii’s duties in enforcing the raising of supplies increased during the third century. Everything we know about the period indicates that the military supply system had become increasingly frayed, with the traditional forms of taxation being replaced with more irregular requisitions.Footnote 44 These requisitions could be arbitrary and destructive for the local population. Would it really make sense to dissolve the main figures responsible for enforcing unpopular taxation right at the point they became most needed?
The presence of frumentarii enforcing the collection of taxes may be connected to the third century's increasing reliance on liturgical officials to raise supplies. While the old system of taxation had relied largely on imperial officials, the Empire was now dependent upon the villages providing the soldiers with supplies themselves as extraordinary liturgical obligations.Footnote 45 This increase in liturgical positions has been noted throughout the later third century and the excessive use of this supply method is likely one cause of the complaints in Asia.Footnote 46
As a military unit tasked with supply, the frumentarii were the obvious choice for this, although under Philip at least (or more accurately under his brother Priscus who was in charge of the eastern provinces as rector Orientis) there seems to have been some experimentation with other units. One of the few facts known about Priscus’ command of the East is that he taxed the provinces heavily.Footnote 47 He was not afraid to alter the existing system and our best-documented province, Egypt, shows clear signs of a major reform during this period. Although the specifics of the reform are now unclear, it involved a shift in the officials responsible for taxation and the creation of new liturgies.Footnote 48 The appearance of the new unit known as kolletiones is likely to be a similar innovation. As the provinces struggled under these new burdens, the easiest solution would have been to send soldiers out to enforce these new liturgies. This may account for the increased burden and the appearance of kolletiones, but when looking at those responsible for these duties it was the frumentarii that the locals were most familiar with and it was the frumentarii who remained. A pair of such figures was commemorated in Aphrodisias ten years after the petitions were made.Footnote 49 The kolletiones do not appear in our sources again.
As the standard figures involved in raising supplies the frumentarii were increasingly called on to deal with the raising of supplies in extraordinary circumstances. The third century was nothing but a series of extraordinary circumstances and their appearance became ubiquitous. The enforcement of military supply was at the heart of their military policing duties, and these continued right until their dissolution.
THE END OF THE FRVMENTARII
This interpretation of their duties provides an alternate explanation for the demise of the frumentarii. Diocletian abolished them during his reign, an act met with much praise according to Aurelius Victor, but the question of why he did so is never answered (Aur. Vict. Caes. 39.44). That he did it for moral reasons seems doubtful. The frumentarii must have proved effective or there would not have been such hatred of them, and utility generally outweighs ethics. It is possible that he did it to curry favour with a specific group or for some other political reason that is no longer obvious. However, if we look at their functions, we can see a clear reason for their dissolution: they were no longer necessary.
As part of Diocletian's reforms a new courier unit called the agentes in rebus was created.Footnote 50 This is the same unit that Aurelius Victor and Jerome explicitly described as a replacement for the frumentarii.Footnote 51 They had in fact several advantages over their predecessors. The frumentarii had always been a decentralized unit. They had risen up on an ad hoc basis from the various legions of the Empire and, despite some efforts at centralization, they never lost their connection to specific legions and provinces.Footnote 52 The agentes in rebus, on the other hand, were a centralized force, being run as a schola in the central administration and integrated more carefully with the cursus publicus.Footnote 53 They had no connection to army units (now increased in number and always a source of potentially dangerous loyalties) or to specific provinces. With their creation the frumentarii became unnecessary and redundant as special couriers.
Meanwhile, another change was undermining their most basic reason for existing. As one of his overarching reforms Diocletian restructured the tax system on a new basis that standardized the irregular requisitions of years past and turned them into a more predictable system of taxation known as the annona militaris. With this system, supplies for the army were raised through taxes in kind collected by regularized liturgical officials. A detailed census was made and the amounts needed in tax from each village were worked out in advance and posted to the various villages.Footnote 54 With this comparative clarity of obligations the taxpayers would have a harder time avoiding their taxes.
With this new system in place, the need for enforcement was much lower. Taxation was more predictable and was known months in advance. There were still disputes, of course, but the government preferred to keep the army out of them lest they gained too much power over their own supply.Footnote 55 Late Roman government was a balancing act designed to ensure that no one group had too much power. Military police were needed on occasion but their use in enforcing tax collection was undesired. Instead, the Romans preferred to leave such duties to the local authorities. With the new liturgies that they had once enforced now a standard and more reliable system, the frumentarii had become victims of their own success.
CONCLUSION
To treat the frumentarii as a spy corps is to fundamentally misrepresent their function. Certainly they had duties that involved what must be classified as spying, but these duties essentially rose from their other roles. In a similar way, even though ambassadors’ official role was diplomatic negotiation, they were assumed to be sources for information by both the Romans and their enemies.Footnote 56 Yet, ambassadors were clearly more than just spies. Any emperor seeking out information on his own officials was likely to turn first to the people who had been in direct contact with them. This does not mean that such espionage was their primary purpose.
The role of the frumentarii was directly tied to their supply duties. All their subsequent duties developed from this initial role. Their service as supply agents for the army was not limited to transporting already gathered supplies from granaries, but instead involved their use for collection of the land taxes that provided them with grain. This required them to have substantial enforcement powers, which naturally led to them taking on a military policing role. This role made them essentially the governor's agents, and when they were in Rome it made them the emperor's agents.
This connection to taxation required them to have close ties to the provincial governors who were responsible for the army, and they would have needed to travel constantly between their legions, the villages and the governor. This led to their use as couriers, a role in which they continued once they were centralized in Rome. This does not mean that their initial duties were taken away. Instead, they continued to perform them all until Diocletian's reorganization of the taxation system made them redundant.
