The Appian Way (Via Appia), the oldest and perhaps most famous Roman road, was built by the Censor Appius Claudius Caecus in 312 b.c. Enlarging a track between Rome and the Alban Hills and forming the main route to Greece and the eastern colonies, this so-called queen of roads (regina viarumeters) ran south from the Porta Capena in Rome’s Servian Wall to Capua. It passed through the Appii Forum to the coastal town of Anxur (now Terracina), 60 miles (100 kilometers) from Rome, to which point it was almost straight, despite crossing the steep Alban Hills and the swampy Pontine Marshes. In 190 b.c. it was extended to Brundisium (modern Brindisi) on the Adriatic coast—more than 350 miles (560 kilometers) from the capital and eighteen days’ march for a legion. Parts of it—now called the Via Appia Antica—remain in use after more than 2,000 years.
The medieval proverb “A thousand roads lead man forever toward Rome” was popularized in William Black’s Strange Adventures of a Phaeton (1872) as “All roads lead to Rome.” That was probably once true: the Romans built about 50,000 miles (80,000 kilometers) of paved roads throughout their empire, mainly to expedite movements of the legions. Inevitably, the system was put to wider use and eventually served all kinds of travelers: dignitaries, politicians, commercial traffic of all kinds, and even an official postal service.
Roman engineers efficiently developed road-building techniques to create enduring structures. Usually (but not always), roads were laid upon a carefully constructed embankment (agger) to provide a foundation—rubble laid in such a way as to provide proper drainage—for the base. The dimensions of the agger varied according to the importance of the road. Sometimes it may have been just a small ridge, but on major routes it could be up to 5 feet high and 50 wide (1.5 by 15 meters). For very minor roads no embankment was built, but two rows of curbstones defined the carriageway; the excavation between them was layered with stones and graded material, the topmost sometimes forming the pavement. Overall, the depth of a Roman road from the surface to the bottom of the base was up to 5 feet. It seems that road width varied according to function, importance, and topography. The widest (decumanus maximus) was 40 feet (12.2 meters) wide, while a minor road might be only 8 feet (2.4 meters). Rural thoroughfares were generally 20 feet (6 meters), but all roads became narrower over difficult terrain: some mountain passes, at less than 10 feet, were too narrow (and often too steep) for carts.
Although stone was sometimes transported from a few miles away, local material was normally used. Of course, that practice gave rise to differences in construction along the length of a road, as is evident in the Via Appia. At one place a 3-foot-thick (1-meter) bottom layer of earth and gravel from the neighboring mountains was consolidated between the curbs and covered by a thinner layer of gravel and crushed limestone, also contained by parallel rows of closely placed large stones. Elsewhere, a base layer of sand was covered with another of crushed limestone into which slabs of lava up to 15 inches (50 centimeters) thick were fixed. Stone surfaces were mandatory for urban streets after 174 b.c., but other roads were not always stone-paved, especially in difficult terrain. Like the substructure, surfaces varied according to what materials were locally available: gravel, flint, small broken stones, iron slag, rough concrete, or sometimes fitted flat stones were used. The pavement thickness varied from a couple of inches on some roads to 2 feet (0.6 meter) at the crown of others. Surfaces sloped down—as steeply as 1 in 15—from the center, to allow rainwater runoff into flanking ditches.
Roman roads were strong enough to support half-ton metal-wheeled wagons, and many were wide enough to accommodate two chariots abreast. Some roads were provided with intentional ruts, intended to guide wagons on difficult stretches. Under normal traffic a paved Roman road lasted up to 100 years. Beginning with the Appian Way, the ancient Roman engineers flung an all-weather communication network across Italy and eventually their empire. The poet Publius Papinius Statius wrote late in the first century a.d.:
- How is it that a journey that once took till sunset
- Now is completed in scarcely two hours?
- Not through the heavens, you fliers, more swiftly
- Wing you, nor cleave you the waters, you vessels.