Most old towns are lost. Look at the maps drawn by Strabo and Ptolomeo: not one in ten is still around. What happened to them all? How can a whole town disappear?
Map of Europe according to Strabo (time of Christ)
Remember that those old towns, sometimes called cities, were no more than villages by our standards. They were a little cuddling together of maybe fifty houses. Most didn’t have a wall around them, so there’s no big orderly pile of rocks to signal archaeologists. And the houses themselves were made of adobe, which after they were abandoned became just a heap of dirt.
It actually helps excavators locate them if an enemy had razed the town because then they find a nice, even, layer of ash as they uncover the mound.
But some of those long-gone cities meant a lot in ancient times and were the scenes of great battles and the hometowns of famous emperors and other famous people. Trajan was from Itálica, now a vast marble junkyard near Seville, and Hannibal’s wife was from Cástulo, a mound just south of Linares.
To look for old Iberian towns like Cástulo archaeologists refer to the maps by the Greeks mentioned above—Strabo and Ptolomeo.
Map of Hispania according to Ptolomeo (first century AD) from LÓPEZ-DAVALILLO LARREA, JULIO: Atlas Histórico de España y Portugal: desde el Paleolítico hasta el siglo XX, Ed. Síntesis, 1999.)
For Roman towns they use two good sources: the Antonine Itinerary and the Vicarello Cups.
The Antonine Itinerary was probably made at the beginning of the third century. It charts thirty-four main roads and all the cities and towns, with the distance between them in Roman miles (1481 meters). And even better, it records partial distances between mansio and mansio, that is, between points that represented a days’ march and which served as resting stops and places to change horses.
The other great source, the Vicarello Cups, are four silver cylinders engraved with all the stops on the trip between a shrine in northern Italy (the Aquae Apollinares) and the temple of Hercules in Cadiz, Spain. The cups are exvotos offered by Spaniards who made the pilgrimage about the end of the first century. Like the Antonine Itinerary, the cups list all the towns and cities on the way, plus the mansioni and the distances between them.
Already in prehistoric times, there were two main roads around the peninsula. At first the Romans used and improved those. The oldest and most travelled was precisely the route on the Vicarello Cups: the route through the Pyrenees and down the western and southern coasts all the way to Cadiz.
That they called the Via Herculea or later, the Via Augustea.
The other famous road was the Via de la Plata, which paralleled the modern Portuguese-Spanish border. It went from Mérida to the rich mineral mines in Galicia.
The road along the Portuguese coast and a northern route straight to the gold mines and Galicia were the other Mother Roads.
Here is a map of Hispania (Spain in Roman times). For a large version click here