An inscription dating from the end of the 2nd century endorses Nais as a municipium – a Roman town with certain self-management rights, as it mentions the name of Marcus Aurelius Posidonius, a decurion of the Nais Municipium. The other two decurions mentioned in the inscriptions are probably from Nais too, namely Aurelius Vitalis and Aurelius Lupus, both of them town decurions, although Nais is not explicitly mentioned on the monuments. The data obtained from the monuments are important for broadening knowledge about the town history, its structure and development, being that the municipal rights were given only to bigger, Romanized centers, granting certain rights (self-management, territory, etc.) significant for the further development of the town. There is no reliable data indicating when exactly Nais got the status of a municipium. All three decurions have the gentile name Aurelius which they could have gotten after several emperors from the 2nd and 3rd centuries (Marcus Aurelius, Commodus, Caracalla, Severus Alexander and Claudius II). It is believed that the town was granted the satatus of a municipium under marcus Aurelius, during the Marcomannic Wars.
Deciphered text of the monument dedicated to Marcus Aurelius Posidonius, a decurion of the Nais Municipium:
I(ovi) O(ptimo) M(aximo)
M(arcus) AVR(elius) Posidonius
d(ecurio) m(unicipii) N(aissi)
v(otum) p(osuit)