The area was inhabited from the 5th century BC by Iberians, mainly in the Ebro Valley, who had commercial contacts with the Greeks and Phoenicians settled on the coast.

Tarraco is first mentioned after the arrival of Gnaeus Cornelius Scipio Calvus at Empúries in 218 BC at the start of the Second Punic War which began the Roman conquest of Hispania.

In 217 BC Roman reinforcements arrived under the command of Publius Scipio, and he and his brother Gnaeus Cornelius are attributed with the enhanced fortification of Tarraco and the establishment of a military port.

[4] The population was largely loyal to the Romans during the war and the fishermen of Tarraco (piscatores Tarraconenses) served with their boats during the siege of Carthago Nova.

There was therefore a strong military presence during this period, possibly in the highest area of what is currently the city's historic quarter, called the Part Alta.

In the same year Augustus went to Spain to monitor the campaigns in Cantabria and due to his poor health he preferred to stay in Tarraco.

A milestone, found in Tarragona's Plaça de Braus, mentions the road between 12 and 6 BC, leading to Barcino to the north-east and Dertosa, Saguntum and (Valentia) to the south.

[11] Tarraco under Augustus and Tiberius minted its own coins with depictions of the imperial cult and the inscription CVT, CVTT o CVTTAR.

[15] This period also saw the defeat of the struggle against the Emperor Clodius Albinus, who was supported by the governor of Tarraconensis Novio, Lucius Rufo.

There started being fewer influential merchants in the ordo decurionum (civil administration) and more patroni (large landowners and public senior officials).

The invasions in about 260[17] by groups of both Franks and Alemanni created hardships for a decade but excavations have not shown effects of these raids within the city and destruction has only been seen in the harbour area and outside the walls.

The Roman Aqueduct de les Ferreres, also called Pont del Diable (Devil's Bridge), crosses a valley about 4 km (2.5 mi) from the city.

The Roman tomb, called Torre dels Escipions (Tower of the Scipios), lies 1.5 km (0.93 mi) to the north-west of the city.

[20] UNESCO included the ruins of the ancient Roman city of Tarraco on its list of World Heritage Sites, because they meet two criteria:[21] Criterion ii.