The Romans overran Gaul (today's France) in seven years, but it took them almost two centuries to completely take over Iberia. The leader of the Lusitanians, Viriathus, led his people in a triumphant campaign against the Romans, which led to his death at the hands of hired assassins. After Viriathus' death, the Romans were able to take over, and the Lusitanians withdrew to hilltop villages of the rural northwest and maintained resistance for several generations, with occasional raids on the settled territory. The Romans settled everywhere, but their numbers in the north was comparatively small. The south was more to their liking, which was better for growing wheat, olives, and grapes. They eventually imposed their language upon the entire peninsula, and their code of law was applied, which was also ultimately the basis of the Portuguese legal code. Forums, temples and law courts were built in the cities, large-scale agriculture was conducted, and the plow was introduced. Roads and bridges (still in evidence throughout Portugal) were created, as well as a system of large farming estates called Latifundios still seen in the area of Alentejo.
Under Decimus Junius Brutus and Julius Caesar, a capital was established at Olisipo (Lisbon), and around 25 BC, Augustus divided the peninsula into several provinces, naming much of the area that eventually became Portugal "Lusitania." Where to see Roman Portugal: In the city of Evora are the impressive remains of the 2nd century Temple of Diana, with 14 Corinthian columns. The Roman town of Conimbriga, founded in the 2nd century B.C., has some of the best preserved Roman ruins in Iberia, with remains of walls, columns used for structural or decorative purposes, classical ornamentation, an aqueduct, fountains and baths with magnificent mosaics, some of which can also be seen at the site museum. There are also Roman remains at Estoi in central Algarve, with some tantalizing fragments of fish mosaics in a former bathing chamber, as well as a Roman villa at Pisões near the city of Beja showing extensive floor mosaics and fragments of decorated walls, baths, a bathing pool, and hypocaust. There are also remains of Roman buildings in Beja, and a Roman bridge in the town of Chaves.