The main evidence of the initial Roman presence is a fortified enclosure built on the summit of Tarragona hill, overlooking the indigenous settlement, the port and the mouth of the River Francolí. The bases for the urban layout of Tarraco were set during the second half of the 2nd century BC with the extension of the fortified enclosure to encompass part of the ancient Iberian settlement. The basic infrastructure for the collection, distribution and elimination of water were installed and the main urban sectors were delimited.
In 49 BC, a grand assembly called by Caesar was held in Tarraco. This was probably when the town received the statute of colony with the name Colonia Iulia Urbs Triumphalis Tarraco –attributed to the Galeria tribe– for the support provided in the military campaign against Pompey. Augustus’ long stay in Tarraco from 26 to 25 BC, as he convalesced from an illness, contributed decisively to the town’s development and it was promoted to capital of the provincia Hispania citerior or Tarraconensis as part of the reform programme undertaken by the princeps. It was at this time that the Republican-period public square was turned into the colonial forum, the theatre was built, and a temple was dedicated posthumously to the deified Augustus.