The Persian Royal Mail
In 500 BC, the Persian Empire was the greatest empire the world had ever seen. Its territory stretched from the Indus River to the Black Sea and the coast of North Africa. Within its borders, the empire ruled over as much as 20% of the world’s population.
The empire contained dozens of formerly independent states and dozens of languages. Administering this massive realm required new systems of control than anything that had been used before. The Babylonians, Assyrians, Hittites and Egyptians had each controlled a small fraction of the territory now ruled by the Persians. To administer the empire, Cyrus the Great created and Darius I refined the division of the empire into 23 satrapies. Each satrap was a viceroy of the Shahanshah (“king of kings”) who ruled in the capital. The satraps exercised the authority of the king in governing and managing the provinces.
The satraps were not kings or vassal rulers, rather, they served at the pleasure of the Persian monarch. Administering the provinces, therefore, required the ability to send rapid communications between satraps and the capital. The king needed to be kept abreast of the situation in all parts of the empire in order to make well-informed decisions in a timely manner. Conversely, the king needed to be able to rapidly send orders back to different parts of the empire. If the satraps were given too much autonomy to take independent action without waiting for a word from the king, they could develop separatist tendencies and become rebellious. 
Previous empires in the ancient Near East had operated messenger systems for official business. The Assyrian mail system dated back to 1800 BC as evidenced by numerous letters found at Karum Kanesh in southeastern Anatolia. The Hittites and Egyptians also operated relay systems of messengers to transmit official business.
The more immediate antecedent, however, was the mail service of the neo-Assyrian empire. The Assyrians had built an empire larger than any that had come before, and therefore faced some of the same communications problems on a smaller scale which the Persians would later face. The Assyrians created a system of stations along major roads, situated about a day’s journey apart from each other where messengers could stop, rest and change horses. This relay system allowed messages to be rapidly carried throughout the empire. It took a courier from Nineveh only a few days to reach the Levant with a message.
First, the Persian Empire needed roads to enable communications. Previous civilizations had built plenty of roads to varying degrees of complexity, but no road network ran the distance of the Persian empire. Cyrus the Great’s solution to this problem was to connect segments of pre-existing roads into a massive highway which ran from Sardis on the Aegean coast of Anatolia to Susa, one of the four capital cities of the Persian Empire. Constructed in much the same way that smaller highways are expanded and connected to form interstates in the modern United States, the Persian highway was dubbed the Royal Road.
The Royal Road’s route can be traced based on the descriptions of it left by Herodotus as well as remains of ancient roads and bridges. Beginning in Sardis, the first sections were based on an earlier Phrygian road which ran across the central plains of Anatolia. From Phrygia, the road crossed the Halys River into Cappadocia. A “huge guardhouse” and gates were built at the river to control access to the road. The other end of the Cappadocian leg was guarded by two more guardhouses and accompanying gates. From there, the road crossed the great Euphrates and Tigris rivers and ran on to the Persian capital of Susa.
There was also a southern route which has been traced but was not mentioned by Herodotus and may have been added at a later date, which ran from Sardis through southern Anatolia, into Cilicia. This route passed through the Cilician Gates, a narrow mountain pass guarded by two massive fortresses. According to Xenophon, who traveled the southern route in 401 BC, “A river, called the Carsus, a hundred feet in breadth, runs between the two fortresses. The whole space between the fortifications was six hundred yards, and it was out of the question to force a way through, since the pass was narrow, and the walls extended to the sea, and above them were sheer cliffs.”
Just as the Persian Royal Road was an expansion of previous roads used to connect smaller empires, so its accompanying courier system was a scaled up version of previous courier routes. According to Xenophon, Cyrus the Great first instituted the Persian mail system. Cyrus may have founded the mail system, but like the Royal Road itself it likely evolved over time under successive monarchs.
At its height, the Persian mail consisted of a system of mounted couriers and rest stops. Cyrus conducted experiments to determine the average distance that a horse could cover in one day’s riding without being ruined. This showed how far apart the rest stations had to be in order to maximize the system’s efficiency.
Each station along the route had a postmaster whose job was to oversee operations, receive messages and route them to their proper destination. Stables where fresh horses were kept were part of the post. The system worked by relay: A courier left one station and reached the next in a day’s riding. When he arrived, the messages he was carrying were handed off to another courier with a fresh horse, who carried them on to the next station, and so on. The previous courier and his horse rested, and then returned to his home station to await the next message to be carried. In times of great urgency, the system could even operate 24/7, with messengers being put on duty in shifts. When a message from the previous station arrived, it was immediately handed off to a night rider who carried it to the next station.
The Greeks had a high level of respect for the Persian mail system. Xenophon wrote of the Persian couriers that “some say they make their way swifter than cranes, but though they are wrong in that assertion, it is manifest that that this is the quickest of all modes of traveling for men by land.” Herodotus famously wrote that “And neither snow nor rain nor heat nor dark of night keeps them from completing their appointed course as swiftly as possible.”
The Persian mail system allowed dispatches to travel at speeds far greater than could be managed otherwise. A dispatch from Sardis could reach Susa in as little as nine days, a distance which Herodotus tells us took 90 days to walk. On the other hand, the system was clearly set up to maximize speed at the expense of volume. The couriers must have been reserved for high priority messages of royal importance, where cost was no object compared to the need to transmit the information as quickly as possible.
High priority government messages must of necessity have contained important, confidential and time-sensitive information. As a result, the Persian mail system served an intelligence function, keeping the king informed of events on the far corners of the empire. Xenophon recognized and praised this feature of the system, saying that “it is right that a sovereign should have immediate intelligence of everything, and give immediate attention to it.” Rapidly learning what was happening in the far reaches of the empire meant that the Persian monarchs could rapidly respond to everything, leading to more effective rule as the king obtained information and made decisions faster than his enemies anticipated.
An example of this system in action may be recorded by Xenophon in his account of the Persian Expedition. After the death of the Persian king Darius II in 405 BC, his eldest son Artaxerxes II took the throne. However, Darius’ younger son Cyrus resented this, and in 401 BC he hired an army of Greek mercenaries in an ill-conceived scheme to depose Artaxerxes and seize power for himself. Cyrus led his army from Sardis on along the course of the Royal Road to the Cilician Gates. Due to his need to raise troops along the way, as well as discontent among the mercenaries, the journey from Sardis to the Cilician Gates took four months.
He was expecting a fight for the forts that guarded the pass, but found them deserted. Abrocomas, the local satrap, had taken his forces to join Artaxerxes II’s army rather than make a stand at the forts. Clearly, the Persian communications system was allowing Artaxerxes II to exercise a high degree of command and control even from far away. Cyrus then pushed forwards into Syria as quickly as possible. He hoped that rapid movement could catch Artaxerxes II off guard, before he could marshal all of his forces. But as Abrocomas’ retreat showed, Artaxerxes II already knew all about Cyrus’ advance. Orders had already been sent, forces were already in motion and an army was already being marshaled.
When Cyrus marched down Euphrates and arrived at Cunaxa two months later, he met no resistance and assumed that Artaxerxes II did not intend to fight before Babylon. In fact, he was being drawn in, his movements constantly shadowed by cavalry. On September 3, Artaxerxes’ army surprised Cyrus’ force at Cunaxa. Cyrus’ vastly outnumbered force (if we take Xenophon’s proportions without trusting his numbers, Artaxerxes’ force outnumbered Cyrus at least seven to one) was largely routed, except for the Greek hoplite phalanxes on the far right of the line. Cyrus was killed, his force scattered, and Xenophon and the 10,000 Greeks left to make their famous retreat to the Black Sea through hundreds of miles of enemy-held territory.
In this case, Artaxerxes was clearly getting plenty of timely information about Cyrus’ movements, allowing him to use the empire’s strategic depth to buy time to marshal a large army to defeat him. His army’s rapid formation allowed him to surprise and overwhelm Cyrus’ forces.
The Persian mail system could also work in reverse, sending important news home from the Persian army in the field. In 480 BC, Xerxes of Persia sent a message from Greece saying that he had captured Athens. This caused a massive celebration in Susa. The celebration was short lived, for shortly thereafter another messenger arrived bringing news of the Persian defeat at Salamis.
The Persian mail system would survive in some form into medieval times, as part of a postal system called the Chapar Khaneh. The system retained its message and intelligence gathering function, which was later copied by the Mongols. The concept of relay couriers kept cropping up in any place where information needed to travel long distances, such as the Pony Express in the American West, up until the transcontinental telegraph made the concept obsolete overnight. In modern times, Herodotus’ famous statement (in slightly different translation) that “neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds” has become the unofficial motto of the United States Postal Service.
Now, information travels around the world at the speed of light. It’s hard for us to imagine the challenges of communication in a world where messages had to be carried. But, as the Persian mail system showed, ingenuity and a lot of money could provide the best solutions possible at the time.
 Michael Roaf, Cultural Atlas of Mesopotamia and the Ancient Near East (Abingdon, England: Andromeda Oxford Ltd., 1990), 181.
 Peter James and Nick Thorpe, Ancient Inventions (New York: Ballantine Books, 1994), 520-521; The Cambridge Ancient History, Vol. 4 (Cambridge University Press, 2000), 216.
 Roaf, Cultural Atlas of Mesopotamia, 181; A. Kirk Grayson, “Assyrian Rule of Conquered Territory in Ancient Western Asia” in Civilizations of the Ancient Near East, Vol. 2, ed. by Jack Sasson (Peabody, MA: Hendrickson, 1995), 966.
 James and Thorpe, Ancient Inventions, 522; The Cambridge Ancient History, Vol. 4, 216.
 Jona Lendering, “The Persian Royal Road,” http://www.livius.org/ro-rz/royal_road/royal_road.htm (accessed October 17, 2011); Herodotus, The Histories, trans. by Andrea L. Purvis (New York: Anchor Books, 2007), 5.52-53.
 Xenophon, Anabasis, trans. by Rex Warner (Baltimore: Penguin, 1967), 1.4; map and trans. note p. 388-389 in Herodotus, The Histories.
 Xenophon, The Cyropaedia, trans. by J.S. Watson and Henry Dale (London: Henry G. Bohn, 1855), 8.17; Pierre Briant, From Cyrus to Alexander: A History of the Persian Empire (Eisenbrauns, 2002), 62-63.
 Xenophon, The Cyropaedia, 8.17.
 Xenophon, The Cyropaedia, 8.17-18; Herodotus, The Histories, 8.98.
 Xenophon, The Cyropaedia, 8.18.
 Herodotus, The Histories, 8.98.
 James and Thorpe, Ancient Inventions, 522; Herodotus, The Histories, 5.53.
 Xenophon, The Cyropaedia, 8.18.
 Xenophon, Anabasis, 1.2-4.
 Ibid., 1.4.
In fact, Abrocomas’ forces arrived three days late for the battle, so forces from other parts of the empire received messages even quicker.
 Xenophon, Anabasis, 1.7-8.
 Herodotus, The Histories, 8.99.
 James and Thorpe, Ancient Inventions, 522-524.
Image Sources: (Banner) http://en.wikipedia.org/wiki/File:Map_of_the_Achaemenid_Empire.jpg; (Body) http://www3.uakron.edu/ziyaret/finds.html; http://www.third-millennium-library.com/readinghall/GalleryofHistory/Darius_the_Great/Darius_Door.htm; http://www.guide-martine.com/history4.asp; http://en.wikipedia.org/wiki/File:Puertas_Cil%C3%ADcias.jpg; http://mailingservicecenter.com/163/postal-shipping-trivia/motto-misnomer/
Article © Christopher Jones 2011.
This entry was posted on October 19, 2011 by cwjones. It was filed under Persian Period (539-330 BC), Spying and Intelligence, Technology and was tagged with Anatolia, Artaxerxes II, Cilician Gates, Cunaxa, Cyrus the Great, Cyrus the Younger, Darius I, Herodotus, Mesopotamia, Persia, Postal Systems, Royal Road, Xenophon, Xerxes.