A Filing System with Horses Attached

AA courier of the Achaemenid kings could carry a sealed order from Susa to Sardis, some two thousand five hundred kilometres, in nine days; a merchant walking the same road allowed three months for the journey. The arithmetic was repeated, with local variations, wherever a large state tried to govern ground it could not see. Augustus organised the Roman cursus publicus around changing posts set roughly eight Roman miles apart, about twelve kilometres, with larger overnight stations at intervals of some thirty miles; the Mongol yam of the thirteenth century is credited with fourteen hundred stations between the Volga and the Yellow River. The physical shape of these systems is reasonably well established, and so are the headline speeds. What historians have disputed since the 1980s is the cause of the speed: whether such a post ran fast because of what had been built along the road, or because of the paperwork that travelled down it behind every rider.

BMarguerite Ollendorf, who studies comparative administration at the Trevanion Institute in Utrecht, argues for the paperwork. Nobody, she points out, rode anywhere without a warrant: the Roman diploma, issued in the emperor's name and valid for a stated period; the Mongol paiza in bronze or silver; the Chinese tally split between courier and station keeper. Her group has worked through 3,140 station documents recovered from the rubbish mounds of Roman Egypt and dated between AD 30 and AD 290, in which the keeper of each post entered the name of the rider, the hour of arrival and the hour of departure. The registers show a median halt of forty minutes; more revealing to her, they show what followed when the rule was broken, since at least two hundred entries record a delay and name the person answerable for it. A road cannot be held answerable. What the documents describe, in her phrase, is not a highway but a filing system with horses attached.

CThe claim yields a test, and Ollendorf has run it against the third century, when the empire's finances collapsed but its roads did not. Along the eastern trunk routes, where an inspecting officer remained in residence, average transit times between AD 250 and AD 285 lengthened by only about a tenth. Along routes from which the inspectorate was withdrawn the same journeys took, on average, twice as long, although excavation shows the road surfaces were in no worse condition than before. The contrast, however, holds only for mail moving on state warrants. On the minor roads, where local officials carried their own letters and no warrant was involved, the withdrawal of inspection made no measurable difference to delivery times at all, and in two districts of Asia Minor letters appear to have moved marginally faster once the inspectors had gone. Ollendorf therefore calls supervision the thing that held a route to its timetable, not the thing that made the route possible.

DPiers Nantwich, a landscape archaeologist at the University of Aberystwyth, replies that a timetable is worth nothing without the ground beneath it. Of sixty-two relay stations his team has excavated on the Danube and Rhine frontiers, forty-one preserve stabling for more than twenty animals, and the spacing of the sites follows gradient rather than provincial boundaries: on level ground the stations sit about eighteen kilometres apart, in the hill country of Noricum about eleven. Fodder, farriers and fresh mounts, on this reading, set a ceiling that no warrant could raise. Nantwich concedes two things. Stone-built stations survive to be dug and timber ones very largely do not, so his sample over-represents the wealthiest lines. And on the Spanish route from Tarraco to Emerita, resurfaced at great expense around AD 120, recorded journey times did not improve until a separate reform eleven years later placed a resident inspector at every third station, a sequence that suits his opponent's account better than his own.

EBoth cases are shaped by what happens to survive. Papyrus lasts only where it never rains, so the registers Ollendorf reads come almost entirely from one province, and from the province where the central government's grip was tightest; the link she finds between supervision and punctuality may be partly a report on which archives the desert chose to keep. She states this difficulty herself, and adds that it cuts the other way too, since masonry survives where administration does not, so a route may look well engineered and badly run merely because stone outlasts ink. Nantwich accepts the symmetry and observes that the two distortions have a single parent. What irritates the pair of them equally is a convention still standard in general accounts of the subject: rating an early post by the number of stations it kept up rather than by the delivery times it actually achieved, a measure that flatters every ruler who ever ordered a road.

FA settlement is taking shape in which the two accounts are given different questions rather than ranked against each other. On whether a route could exist at all across mountain or desert, the hardware decides, and Ollendorf does not dispute it. On whether an existing route kept to its schedule, the evidence points to supervision, and Nantwich's Spanish sequence is consistent with that reading provided his own qualification about surviving masonry is allowed. What neither can yet reach is the private letter. Merchants' correspondence travelled beside the official mail throughout, sometimes by favour and sometimes by bribe, but no dated series of such letters is long enough to show whether private carriage quickened when the state's did. Both reject the assumption older textbooks made without noticing, that a state able to move a message quickly was thereby a state able to move anything else quickly.