The Mediterranean contributions represented a commercial activity that will constitute a powerful stimulus for the iron metallurgy, promoting the modernization of the tools and the indigenous armament, replacing the old bronze with the iron. There is presence of Phoenician, Greek and Etruscan products.

In the 6th century BCE there are six groups with different social organization: Vascones, Suessetani, Sedetani, Iacetani, Ilergetes and Citerior Celtiberians.

They are Iberized groups with a tendency towards stability, fixing their habitat in durable populations, with dwellings that evolve towards more enduring and stable models. There are many examples in Aragon, among which Cabezo de Monleón in Caspe, Puntal of Fraga, Roquizal del Rullo or Loma de los Brunos.

The type of social organization was based on the family group, consisting of four generations. Self-sufficient societies in which the greater part of the population was dedicated to agricultural and livestock activities. In the Iberian scope the power was monarchical, exercised by a king; there was a democratic assembly with participation of the male population.

There were visible social differentiations and established legal-political statutes.

The Romans arrived and progressed easily into the interior.

In the territorial distribution that Rome made of Hispania, the current Aragon was included in the Hispania Citerior. In the year 197 BCE, Sempronius Tuditanus is the praetor of the Citerior and had to face a general uprising in their territories that ended with the Roman defeat and the own death of Tuditanus. In view of these facts the Senate sent the consul Marcus Porcius Cato with an army of 60000 men. The indigenous peoples of the area were rebelling, except for the Ilergetes who negotiated peace with Cato.

There were different uprisings of the Iberian peoples against the Romans, in 194 BCE sees a general uprising with elimination of half of the Roman army, in 188 BCE Manlius Acidinus Fulvianus, praetor of the Citerior, must confront in Calagurris (Calahorra) with the Celtiberians, in the 184 BCE Terentius Varro did it with the Suessetani, to those who took the capital, Corbio.

In the 1st century BCE Aragon was the scene of the civil war to seize the power of Rome where the governor Quintus Sertorius made Osca (Huesca) the capital of all the territories controlled by them.

Already in the 1st century BCE, the today Aragonese territory became part of the province Tarraconensis and there was the definitive romanization of it creating roads and consolidating ancient Celtiberian and Iberian cities such as Caesaraugusta (Zaragoza), Turiaso (Tarazona), Osca (Huesca) or Bilbilis (Calatayud).

In the middle of the 3rd century the decay of the Roman Empire began. Between the years 264 and 266 the Franks and the Alemanni, two Germanic peoples who passed through the Pyrenees and came to Tarazona, which they sacked. In the agony of the Empire groups of bandits emerged who were dedicated to pillage. The Ebro Valley was ravaged in the 5th century by several gangs of evildoers called Bagaudae.