Roman roads and paved Roman roads in Portugal

The Roman roads — and the paving that surfaced their most demanding sections — constitute the greatest engineering enterprise of antiquity preserved on Portuguese territory. Built mainly between the late first century BC and the third century AD, they brought the province of Lusitania and the south of Gallaecia under imperial administration, linking the principal urban centres — Olisipo (Lisbon), Ebora (Évora), Scallabis (Santarém), Conimbriga, Bracara Augusta (Braga), Aquae Flaviae (Chaves) — to ports, mines and the provincial capital, Emerita Augusta (Mérida). More than simple tracks, they were works in the service of administration, the army and commerce, and many of their routes remain fossilised beneath national roads and rural paths.

A network in the service of the Empire

Our knowledge of the road system rests above all on the Antonine Itinerary, a late-imperial compilation that enumerates the official routes, the posting stations (mansiones) and the intermediate distances expressed in Roman miles, of about 1480 metres. Of the some thirty-four roads attributed to Hispania, roughly eleven crossed the present territory of Portugal.

Among the main axes are the routes between Olisipo and Emerita Augusta — such as Via XVI —, the link from Olisipo to Bracara Augusta, and the group of north-western roads that, from Braga, headed for Asturica Augusta (Astorga): Via XVII by Chaves, Via XVIII or Via Nova through the Gerês, and Via XIX by Ponte de Lima. At the southern extremity, branches joined Salacia, Pax Iulia (Beja) and Ossonoba (Faro), linking the Algarve with the Alentejo interior.

Each road was identified by a number and sometimes by a descriptive epithet. Via XX, called per loca maritima — “through the maritime places” —, followed the Galician coast, and the fact that its distances are given in stadia rather than miles betrays a coastal itinerary matrix.

Technique and construction

Contrary to the common image of a uniform paved road, most Hispanic roads had a surface of beaten earth or gravel, with stone paving reserved for urban stretches, slopes and difficult crossings.

The image of the Roman road as a series of superimposed layers — statumen, rudus, nucleus and a surface of slabs — describes chiefly the major urban axes. In rural and mountainous areas the most common solution was a platform of compacted gravel and sand, bordered by kerbs, with stone paving reserved for critical points: steep slopes, damp passages or approaches to bridges.

Construction adapted to the terrain. Soundings along stretches such as that of Via XVIII have revealed variable strata — sands, river pebbles and coarser gravel — often laid directly on the bedrock, without the drainage trenches and rigid stratigraphy described for Italy. This flexibility explains why so many segments are today confused with medieval tracks: the Roman road was, above all, a practical solution for moving people and goods over hundreds of kilometres.

Milestones and bridges

The milestones are the most reliable testimony of the network. They were stone columns, frequently about two metres high, which marked the miles and bore inscriptions with the emperor’s name, distances and references to repair works. Their epigraphic reading makes it possible to date phases of construction and restoration and to associate sections with specific emperors. In Portugal they are concentrated mainly north of the Douro.

Inseparable from the roads are the Roman bridges, which secured the crossing of rivers and streams, and many of which remained in use for centuries — such as the notable Roman bridge of Chaves, over the Tâmega, in ancient Aquae Flaviae. The road layout also structured settlement: stations such as Bobadela or the great urban centres studied by Roman archaeology in Portugal owe much of their importance to their position along these axes.

The Geira, the best-preserved road

The most remarkable case is the Geira, or Via XVIII, which crosses the Peneda-Gerês National Park and traverses the range by the Portela do Homem. Laid out under Vespasian and continued under Titus and Domitian, it is one of the best-preserved and most studied Roman roads in the north-west of the Iberian Peninsula, and the one where the largest number of milestones has survived: of the 140 milestones inventoried on the Portuguese section, 102 remain in situ. The Portuguese section was classified as a National Monument in 2013.

Other stretches of paving, reused milestones and scattered road surfaces across the North, Centre and Alentejo bear witness to the density of this network, which forms part of the wider range of built heritage typologies and of Roman and pre-Roman Portugal.

A lasting legacy

The road network durably shaped the geography of Portugal. Numerous medieval tracks, pilgrimage routes and even modern roads follow alignments inherited from Rome, and the study of its remains — inseparable from Roman architecture in Portugal — continues to provide decisive data on the economy, administration and circulation of antiquity.

Recognising a regular embankment, a granite kerb or an uninscribed marker in the landscape is often the key to restoring visibility to an infrastructure that structured the territory for almost two millennia. Every recovered milestone and every identified stretch of paving is a piece that allows the outline of an empire to be reconstructed at the scale of the landscape.