Fig. 12.1 Roman road construction. (U.S. Bureau of Public Roads)
Roman roads (see [Fig. 4.1]) echoing to the measured tread of marching legions, had made a large contribution to unifying Italy by the time the last great consular highway, the Via Aemilia, opened up the Po valley from Ariminum to Placentia in 187 B.C., but their work of carrying commerce and ideas was unceasing. Of course there were roads in Italy before the Romans: the name and route of the Via Salaria, from the salt-pans at the Tiber’s mouth up the valley into the Apennines, suggest that it must have been in use since prehistoric times. The Via Latina, named not for a Roman consul but for a people potent in central Italy until the Romans broke their league in 338 B.C., must count as a pre-Roman road, and its winding course along the foothills must antedate the draining of the Pomptine marshes and the laying down of the straight course across them from Rome to Tarracina and thence to Capua of the regina viarum, the queen of roads, the Via Appia. It bears the name of a Roman censor of 312 B.C. This is the first of the great highways, and it deserves its fame for its bold conquest of natural obstacles, its arrow-straight course across the marshes, but its gravel surface was not replaced by stone pavement until 293 B.C., and then only as far as the suburb of Bovillae. And its course, like that of many another Roman road, was not always so arrow-straight. In the hills behind Tarracina it followed the contours; it was not until Trajan’s time that another bold stroke of engineering cut through the high, rocky Pesco Montano to let the road pass by the more direct coastal route. (Some authorities hold that the Romans preferred straight roads because the front axles of their vehicles were rigid.) Trajan’s engineers showed their pride in their work by incising monumental Roman numerals, still visible, to mark the depth of the cut every ten feet from the top down, until the road level was triumphantly reached at CXX.
Along the Appia, and the other consular roads radiating from Rome, traces of the ancient stone paving are occasionally preserved. The paving blocks are usually selce (flint), polygonal in shape and closely fitted without mortar. While most Roman roads prove on archaeological examination to consist of paving blocks laid in a trench and packed with earth and selce chips, it will be worthwhile to record the ideal method of laying a pavement—strictly speaking a mosaic pavement—as recommended by the architect Vitruvius, a contemporary of Augustus. The method illustrates the Roman engineer’s infinite capacity for taking pains.
After the field engineer (1 in the reconstruction, [Fig. 12.1]), assisted by the stake man (2), had aligned the road with his groma, he ran levels with the chorobates (3) with the roadman’s help (4). A plow (5) was used to loosen earth and mark road margins; then workmen dug marginal trenches (6) to the depth desired for the solid foundations. Laborers (7) shoveled loose earth and carried it away in baskets. The next step was to consolidate the roadbed with a tamper (8). Now the roadbed was ready for its foundation, the pavimentum (9), lime mortar or sand laid to form a level base. Next came the statumen, or first course (10), fist-size stones, cemented together with mortar or clay, the thickness varying from ten inches to two feet. Over this was laid the rudus or second course (11), nine to twelve inches of lime concrete, grouted with broken stone and pottery fragments. Next the nucleus, or third course (12), concrete made of gravel or coarse sand mixed with hot lime, placed in layers and compacted with a roller. Its thickness was one foot at the sides, eighteen inches at the crown of the road. Finally, the summum dorsum or top course (13), polygonal blocks of selce six inches or more thick, carefully fitted and set in the nucleus while the concrete was still soft. Sometimes, when archaeologists have taken up a stretch of Roman road, they have found the selce blocks rutted on the under side: the economical contractors, happily untroubled by high-priced labor, had repaired their road by turning the worn blocks upside down. Standard curbs (14a and b) were two feet wide and eighteen inches high; paved footpaths (15a and b) often ran outside them. Conduits (16) under the curb, with arched outlets (17) opening beside the right of way, took care of draining surface water. Milestones (18) marked the distance from Rome and the name of the Emperor responsible for repairs. From the names of successive Emperors on milestones of the same road, archaeologists have calculated that the average life of a highway was thirty to forty years.
Two points should be emphasized: first, this represents an ideal method of construction, not often exemplified in practice; second, to a modern engineer a road like this would seem insufficiently elastic, a five-foot wall in the flat, too rigid for the stresses and strains to which it was subjected. Hence perhaps the frequent need for repairs, but Roman traffic was lighter than ours, and the very fact that we can write about the roads at all is a tribute to their durability. Upon roads like these, under the Empire, travelled the Imperial posting service, with relays of messengers, and post-houses where horses and carriages could be changed. Under exceptional conditions the Emperor Tiberius, using this service, once travelled 180 miles in a day, a rate of speed not equalled on European roads until the nineteenth century.
The next major road laid out after the Appia must have been the Valeria, which was needed for eastward communication via Tivoli with the new colony of Alba Fucens, founded, as we saw, in 303 B.C. Archaeology has shown that in general the foundation of a colony precedes the laying down of the metalled military road. This is true of Cosa (foundation date of the colony, 273 B.C.; probable date of the Via Aurelia which served it, about 241); of Ariminum (founded 268 B.C.; reached by the Via Flaminia in 220), and of the Roman colonies in the Po valley; e.g., Bononia (Bologna: founded 189 B.C.; reached by the Via Aemilia after 187). The full extension of the Via Valeria beyond Alba to the Adriatic had to await the pacification of the Samnite tribes of central Italy and the granting of citizenship to Italians after the “Social” War, in 89 B.C. Milestones on this last stretch belong to Claudius’ reign (A.D. 41–54).
A recent (1957) survey of the central section of the Valeria by the Dutch scholar C. C. Van Essen illustrates the methods and results of archaeologists working in the field with topographical problems. Faced with the palimpsest of more than two millennia overlying the road he wanted to trace, Van Essen paid particular attention to such roadmarks as Roman milestones; ancient tombs (which regularly lined Roman roads in the vicinity of towns); supporting walls, in Roman headers-and-stretchers; rock-hewn causeways; bridges, where Roman materials and workmanship can be distinguished from modern (as has been recently done for the bridges of the Via Flaminia by Michael Ballance of the British School at Rome; there the striking thing is the predominance and good quality of the work done under Augustus, who had a vested interest in assuring efficient communications with his veterans dispersed in colonies in north Italy). Stretches of ancient pavement are rare on the Valeria, having been destroyed by medieval and modern resurfacing, by the plow, and by torrents and earthquakes, but the trench in which it was bedded can often be distinguished on air photographs. What struck Van Essen chiefly was the frequency with which the ancient Via Valeria would run straight on, with steep gradients, where the modern road resorts to sweeping curves or hairpin bends. Ancient vehicles, the heaviest of which were perhaps only a quarter the weight of a modern light European car (Roman wagon, perhaps 440 pounds; Volkswagen, 1650), and scarcely ever carried loads of over 1100 pounds, would be less troubled by steep gradients than a modern heavy truck. Even so, at Tagliacozzo, about six miles on the Rome side of Alba Fucens, the grade is so steep that Van Essen supposes the ancient inhabitants hired out oxen to help the straining horses on the upslope. Van Essen noted that the telegraph lines, following the comparatively straight course of the ancient road, often gave a clue to its presence. The ancient sixty-eighth milestone of the Valeria, found, as we saw, within the walls of Alba Fucens, provides a good comparison of the respective lengths of the ancient and the modern roads. Since the Roman mile (4861 English feet) was slightly shorter than the English, sixty-eight Roman miles corresponds to slightly over sixty-two English miles, whereas the modern Via Valeria covers about 113 kilometers, or approximately seventy miles, to reach Alba.
Archaeologists have not confined their interests to the great consular roads. Minor highways in areas away from the main stream of traffic are often more rewarding, since they tend to be better preserved, and offer some chance to trace the pre-Roman systems that underlie or intersect them. The district just north of Rome has been surveyed in this way by members of the British School at Rome since 1954, only just in time, for there prevails in this region a situation analogous to the rapid disappearance of Indian remains in the American West with the building of the great hydroelectric dams. In the country north of Rome, since World War II, there has been an extensive program of land expropriation, reclamation, and resettlement of small farmers, an excellent thing for rehabilitating the Italian peasantry, but fatal for archaeological remains, since the plan involves the use of the deep plow, an ideal instrument for obliterating traces of ancient roadways. Thus it is that members and friends of the British School, spurred on by the Director, John Ward Perkins, a worthy successor of the indefatigable Thomas Ashby, are to be seen braving wind and weather as they scour the countryside for Roman and pre-Roman roads from Veii to beyond Cività Castellana, armed with large-scale maps, air photographs, and brown paper bags for collecting the potsherds which are the evidence of ancient roadside habitation.
The British School’s most significant recent work has been carried on from Nepi, a Roman colony allegedly of 383 B.C., twenty-eight miles north-northwest of Rome, and Falerii Novi, about four miles farther north. Falerii Novi was built by the Romans from the ground up in 241 B.C. to house the inhabitants of Falerii Veteres (Cività Castellana) a hostile native Faliscan center, which the Romans completely destroyed. But the old city must have been resettled, for ruts in the third century B.C. road connecting the new city with the old are not of standard Roman width, and were probably made by Faliscan wagons. The cardo of the new settlement is formed by a new road connection with the south, the Via Amerina ([Fig. 12.2]); in the course of exploring this the British archaeologists found traces from which the older road system ([Fig. 12.3]) which it partially supplanted, may be inferred. At Torre dell’ Isola, just north of Nepi, for example, they found, by the wall of a medieval castle, sherds with the cord-impressed chevrons characteristic of Villanovan ware, and part of one of the portable hearths which we met first in the primitive hut on the Palatine in Rome. These sherds provide evidence for habitation here at least as early as on the Palatine. The discovery of similar sherds within the walls of Etruscan Veii suggests a people inferior culturally to the Etruscans, and probably living in subjection to them.
