The cursus publicus (Latin: "the public way"; Ancient Greek: , d?mósios drómos) was the state-run courier and transportation service of the Roman Empire, later inherited by the Byzantine Empire. The Emperor Augustus created it to transport messages, officials, and tax revenues between the provinces and Italy. The service was still fully functioning in the first half of the sixth century in the Byzantine Empire, when the historian Procopius accuses Emperor Justinian of dismantling most of its sections, except for the route leading to the Persian border. The extent of the cursus publicus is shown in the Tabula Peutingeriana, a map of the Roman road network dating from around AD 400.
A series of forts and stations was spread out along the major road systems connecting the regions of the Roman world. The relay points or change stations (stationes) provided horses to dispatch riders and (usually) soldiers as well as vehicles for magistrates or officers of the court. The vehicles were called clabulae, but little is known of them. A diploma, or certificate, issued by the emperor himself was necessary to use the services supplied by the cursus publicus. Abuses of the system existed, for governors and minor appointees used the diplomata to give themselves and their families free transport. Forgeries and stolen diplomata were also used. Pliny the Elder and Trajan write about the necessity of those who wish to send things via the imperial post to keep up-to-date licences.
Another term, perhaps more accurate if less common, for the cursus publicus is the cursus vehicularis, particularly in the period before the reforms of Diocletian. At least one 'Praefectus Vehiculorum', Lucius Volusius Maecianus, is known; he held the office during the reign of Antoninus Pius. Presumably, he had some sort of supervisory responsibility to ensure the effective operation of the network of stations throughout the Empire and to discourage abuse of the facility by those not entitled to use it. There is evidence that inspectors oversaw the functioning of the system in the provinces, and it may be conjectured that they reported to the 'Praefectus' in Rome. However, the office does not seem to have been considered a full-time position because Maecianus was also the law tutor of the young Marcus Aurelius, apparently his main function.
Despite evidence that the government supervised the functioning of the network of stations and, presumably, its development over the centuries, the service was not supplied by a department of state in the same way as, say the modern British Royal Mail. As Altay Coskun notes in a review of Anne Kolb's work done in German, the system "simply provided an infrastructure for magistrates and messengers who traveled through the empire. It consisted of thousands of stations placed along the main roads; these had to supply fresh horses, mules, donkeys, and oxen, as well as carts, food, fodder, and accommodation." It's maintenance was paid for by the provincials. Thus, there was no "department of postal service" with employees paid by the emperor. The one who was sending a missive would have to supply the courier, and the stations had to be supplied out of the resources of the local areas through which the roads passed. As seen in several rescripts and in the correspondence of Trajan and Pliny, the emperor would sometimes pay for the cost of sending an ambassador to Rome along the cursus publicus, particularly in the case of just causes.
Following the reforms of Diocletian and Constantine I, the service was divided in two sections: the fast (Latin: cursus velox, Greek: ? ) and the regular (Latin: cursus clabularis, Greek: ). The fast section provided horses, divided into veredi ("saddle-horses") and parhippi ("pack-horses", and mules, and the slow section provided only oxen. The existence of the 'cursus clabularis' service shows that it was used to move heavy goods as well as to facilitate the travel of high officials and the carriage of government messages. It's maintenance was paid for by the provincials under the supervision of the governors, diocesan vicars and praetorian prefects.
The Romans adapted their state post from the ancient Persian network of the royal mounted couriers, the angarium. As Herodotus reports, the Persians had a remarkably efficient means of transmitting messages important to the functioning of the kingdom, called the Royal Road. The riders would be stationed at a day's ride along the road, and the letters would be handed from one courier to another as they made a journey of a day's length, which allowed messages to travel fast. Augustus, at first, followed the Persian method of having mail handed from one courier to the next, but he soon switched to a system by which one man made the entire journey with the parcel. Although it is possible that a courier service existed for a time under the Roman Republic, the clearest reference by Suetonius suggests that Augustus created the system:
Tacitus says that couriers from Judea and Syria brought news to Vitellius that the legions of the East had sworn allegiance to him, and this also shows that the relay system was displaced by a system in which the original messenger made the entire journey. Augustus modified the Persian system, as Suetonius notes, because a courier who travels the whole distance could be interrogated by the emperor, upon arrival, to receive additional information orally. That may have had the additional advantage of adding security to the post, as one man had the responsibility to answer for the successful delivery of the message. That does not come without a cost, as the Romans could not relay a message as quickly as they could if it passed from one rider to the next.
The cursus operated in Italy and the more advanced provinces. There was only one in Egypt and one in Asia Minor, as Pliny's letters to Trajan attest. It was common for a village to exist every 12 miles (19 km) or so, and there a courier might rest at large, privately owned mansiones. Operated by a manceps, or a business man, the mansiones provided food and lodging, and care and a blacksmith for the horses. The cursus also used communities located along the imperial highways. These towns very often provided food and horses to messengers of the Legions, theoretically receiving reimbursement, and were responsible for the care of their section of the Roman roads. Disputes arose naturally, and for a time the central administration participated more directly.
Costs for the cursus publicus were always high, and its maintenance could not always be guaranteed. Around the time of Nerva, in the late first century, the general cost was transferred to the Fiscus (treasury). Further centralization came during the reign of Hadrian, who created an actual administration under a prefect, who bore the title praefectus vehiculorum. Provinces were always in touch with Rome and one another. The Imperial Post gave the legions the capacity to summon reinforcements and provide status reports before any situation deteriorated too badly. The average citizen sent letters and messages to friends across the sea with slaves and travelling associates. Most news reached its destination eventually. In an effort to restrict abuse of the post whose use Constantius II, emperor, 337-361, had overloaded the service Julian the Apostate, 361-363, restricted the granting of passes to the Praetorian Prefects and himself. This was unworkable. He granted 12 to vicars and 2 to governors one for use within the province and the other for communication to the emperor. Four each were issued to the three proconsuls of Asia, Africa and Achaea. The counts of the Treasury and Crown Estates could obtain warrants whenever they needs since these two departments supplied revenue in gold and the private income of the emperors respectively, matters of the greatest importance. The highest-ranking generals and frontier generals were issued passes, especially those at danger points like Mesopotamia, cf. A.H.M. Jones, The Later Roman Empire, pp. 130, 402. Notwithstanding its enormous costs, in the Eastern Roman Empire the service was still fully functioning in the first half of the sixth century, when the historian Procopius charges Emperor Justinian with the dismantlement of most of its sections, with the exception of the route leading to the Persian border (Secret History 30.1-11). The dromos continued to exist throughout the Byzantine period, supervised for much of it by the logothet?s tou dromou, although this post is not attested before the mid-eighth century and a revival of the service may then have occurred after a substantial gap. It was by then a much reduced service, restricted essentially to the remains of the old oxys dromos. In the west, it survived under the Ostrogoths in Italy, as Cassiodorus reports Theodoric the Great's correspondence.
Procopius provides one of the few direct descriptions of the Roman post that allows an estimation the average rate of travel overland. In the 6th century, he described earlier times:
|"||The earlier Emperors, in order to obtain information as quickly as possible regarding the movements of the enemy in any quarter, sedition, unforeseen accidents in individual cities, and the actions of the governors or other persons in all parts of the Empire, and also in order that the annual tributes might be sent up without danger or delay, had established a rapid service of public couriers throughout their dominion according to the following system. As a day's journey for an active man they fixed eight 'stages,' or sometimes fewer, but as a general rule not less than five. In every stage there were forty horses and a number of grooms in proportion. The couriers appointed for the work, by making use of relays of excellent horses, when engaged in the duties I have mentioned, often covered in a single day, by this means, as great a distance as they would otherwise have covered in ten.||"|
If the distance between stages was known, the distance five stages or eight stages and the average rate at which correspondence moved along the cursus publicus would both be known. That was calculated by A. M. Ramsey in the following way: "It appears from the Jerusalem Itinerary that the mansiones, or night quarters on the roads, were about twenty-five [Roman] miles [23 mi or 37 km] apart, and, as Friedlander points out, the distance between Bethlehem and Alexandria (about 400 Roman miles [368 mi or 592 km]) was reckoned to be sixteen mansiones, that between Edessa and Jerusalem (by Antioch nearly 625 [Roman] miles [574 mi or 924 km]) twenty-five mansiones. Although no Itinerary gives a complete list of mutationes and mansiones for any road, the general rule seems to have been two mutationes between each two mansiones or 23 miles. This would make the 'stage' about eight and a third Roman miles [7.7 mi or 12.4 km]." Therefore, the typical trip was made at the rate of 38 to 62 miles (61-100 km) per day or 5 to 8 stages.
There are several cases in which urgent news or eager officials traveled at a faster rate. There is the journey of Tiberius mentioned by Valerius Maximus, the news of the mutiny of Galba as recorded by Tacitus, and the news of the death of Nero as described by Plutarch. In the last two cases, it is worth keeping in mind that bad news traveled faster than good news, and quite explicitly: a laurel was attached to the correspondence with news of victory, but a feather, as indicating haste, was fixed to the spear of a messenger carrying bad news. In all three cases, as A. M. Ramsey points out, the journey is especially urgent, and the time of travel may be recorded because of its exceptional rapidness. Such cases could not be used to find an average speed of the Roman post for carrying the vast majority of items.
Ramsey, following Wilcken, illustrates the speed of the Roman post over land with examples of the amount of time it would take a message to travel from Rome to Egypt about the accession of a new emperor (in a season other than summer, when the message would travel by sea from Rome to Alexandria). In the case of Pertinax, news of the accession, which took place on January 1, AD 193, took over sixty-three days to reach Egypt, being announced on March 6 in Alexandria. Since the route that would be taken over land consisted of about 3,177 kilometres (1,974 mi)--1,400 kilometres (870 mi) from Rome to Byzantium, including the sea crossing and almost 1,800 kilometres (1,100 mi) from Byzantium to Alexandria)--and since it took about sixty-three days or a little more for the message to arrive in Alexandria, this confirms an average rate of about 32 miles (51 km) per day for this journey.
Another example, based on a Latin inscription, is cited by Ramsey. Gaius Caesar died on February 21, AD 4, in Limyra, which is on the coast of Lycia. The news about his death is found on an inscription dated April 2 at Pisa. The amount of time that the message took to arrive at Pisa is not less than thirty-six days. Since a voyage by sea would be too dangerous at this time of year, the message would be sent over land, a distance of about 1,345 miles (2,165 km). This again confirms the calculation of an average rate of about fifty miles per day.
In his article "New Evidence for the Speed of the Roman Imperial Post," Elliot agrees with A. M. Ramsey that the typical speed was about 50 miles (80 km) per day and illustrates this with another instance, the time that it took news of the proclamation of the emperor Septimius Severus to reach Rome from Carnuntum.
These estimates are for journeys that took place over land, making use of the cursus publicus (or, cursus vehicularis). Lionel Cassons, in his book on ancient sea travel, gives statistics for the amount of time that sixteen voyages took between various ports in the Roman Empire. These voyages, which were made by and recorded by the Romans, are recorded specifically as taking place under favorable wind conditions. Under such conditions, when the average is computed, a vessel could travel by sail at a speed of about 5 knots (9.3 km/h; 5.8 mph) or 120 miles (190 km) per day. Cassons provides another table of ten voyages made under unfavorable conditions. With these voyages, the average speed is about 2 knots (3.7 km/h; 2.3 mph) or 50 miles (80 km) per day.