It was at a later time, in the Flavian era, that the city was granted its ius Latii (Latin Rights) and the status of municipium, boosting the population thereafter. The city sprawled into the western part of the meseta, which had remained unoccupied and especially the whole southern era. Monuments now began to spring up; typical Roman public buildings were built: a commemorative arch at the city entrance; a public building with an arcaded courtyard, in all likelihood the Curia; two baths, one for men and one for women; plus an in antis temple along one of the main streets.
The city, however, did not shed all its native qualities. Most of the houses kept their thatched roofs, eschewing the Roman tegula and imbrex tiles. That said, the living space was completely transformed as compared with the Celtiberian city: new, bigger and functionally compartmented quadrangular spaces were brought in. As from that moment Numantia became economically and politically part of the Roman Empire. The concentration of great farming estates favoured productive specialisation; this led to significant changes in the native structures of dependency and personal relations.