The Via Augusta was the great imperial road of Spain, and as a continuation of the
Vias Julia Augusta,
Aemilia, and
Flaminia, it formed a major link in a chain of roads connecting Rome with the Atlantic Ocean. Its usage allowed the development of cities such as Valentia (Valencia), Saguntum (
Sagunto), Lucentum (
Alicante), Saetabis (
Xàtiva), and Ilici (
Elche). The Roman road engineers naturally considered the surrounding environment and the slope of the land when determining the course of the road, taking into account the existing old
Iberian roads as well. The average width was between four and six metres, although there are some sections that were ten or fourteen metres wide. The sidewalks (
margines or
crepidines), built only near the cities, were between three and ten metres wide on each side. Starting from Coll de Pertús pass in the Pyrenees, the Via Augusta ran south and southwest to the upper reaches of the River Baetis, and from that area on through Baetica to Gades. From the point where the road crossed the Baetis, however, a new system began. The river in that region formed the boundary between Baetica and Tarraconensis, and there a bridge with an
arch, the
Ianus Augusti, was erected in honor of Augustus. From this arch all the rest of the
milestones on the way to Gades were numbered. Only the
opus caementicium foundations of the arch remain extant. It is located in the northeastern sector of the
Guadalquivir Basin, a
foreland basin situated between the
Iberian Massif to the north and the
Betic Cordillera to the south. Milestones were placed on the edge of Roman roads to indicate distances between
capitas (starting points), at a distance of a thousand paces between the milestones (a pace was a Roman double step called a
mille passum) equivalent to a Roman mile, i.e., 1.480 metres, hence its name. The milestones were cylindrical stone columns of granite or sandstone between 2 and 3 metres high and 50 to 80 cm in diameter, set on a square base. They were inscribed with information referring to the road: the name of the builder or restorer, the name of the nearest station and the distance, and sometimes the point of departure (
caput viae) or of arrival (
terminus viae). Agrippa then went to Hispania in 19-18 BC to personally direct the
war against the Cantabrians in the north of the peninsula; Augustus himself returned to Hispania and remained for a period between 16 and 13 BC doing administrative work. He and his advisors set about devising an ambitious programme to restructure the administration of the territory, its primary objectives being the establishment of new cities, the construction of roads connecting them, and the distribution of large areas of land to be parcelled out among veteran professional soldiers. With the complete subjugation of Hispania, Augustus determined to lay out a proper road system like that which Agrippa had built in Gaul, and the basic network appears to have been completed in his reign. He repaired and relaid the coastal road from Tarraco (the imperial headquarters during his residence, Augustus made it the capital of
Hispania Tarraconensis), through Valentia to Carthago Nova (Cartagena), as well as the road through the Baetis valley by way of Corduba and
Hispalis to Gades itself, and in this section a large number of milestones bearing his name have been found. The isolation of Hispania from the rest of the Mediterranean world was a circumstance addressed by the building of Augustus' road network. The itineraries and milestones, as well as traces of the ancient roads, suggest that this was an intensive project. There were four important routes between the
conventus capitals of Bracara Augusta (
Braga) and Asturica Augusta (
Astorga), the third hub of the system being the conventus capital Lucus Augusti (
Lugo). Caesaraugusta (
Zaragoza) and Carthago Nova were conventus capital cities that were also crossroads and the terminuses (
capita) of roads. There it met the road following the course of the
Ebro and then into the region of north-central Hispania. Asturica Augusta, the
terminus of the "silver route", was an important junction, where the highways to Lusitania and the Cantabrian coast intersected. It later became the celebrated pilgrimage road to
Santiago de Compostela. In the south, Emerita and Gades were connected by the Hispalis road. In Hispalis the road joined the branch of the Via Augusta which started in
Acci (also Accitum) and veered inland to Corduba, Astigi (Écija), and Carmo. This was the main layout of the Roman road system in Hispania; together with the network of localised roads, they covered about . There was a road built by him from
Ilerda to Caesaraugusta, crossing the
Ebro by a wooden bridge according to Strabo, and apparently one from Aesuris to
Pax Julia, up the course of the river
Anas. Augustus had surrounded Hispania with a great circle of roads, with one or two branches reaching inland. In contrast to Gaul, where Agrippa had laid out four or five roads radiating from a central hub, here there was the perimeter of a wheel, so to speak, and it was the task of succeeding emperors to fill in the spokes and build more direct cross-country routes. The Via Augusta was originally a
via militaris, i.e., a military road built by
legionaries of the
Roman army; these units constructed a substantial part of the road network, especially at the beginning of the empire. These roads remained strategically important, but their main purpose was for general communications, as shown by an inscription on a fragmentary milestone found near Corduba (Córdoba). Here, in the year 90,
Domitian ordered the restoration of the Via Augusta, which had fallen into disrepair. This section of the road was designated a
via miltaris, according to the inscription: In English: ==Cities through which the Via Augusta passed==