Neapolis was founded around 470 B.C., not far from the ancient settlement of Parthenope - the Palaepolis -, by the Cumaeans, who had succeeded in checking Etruscan expansion and thus gaining control of the entire Gulf of Naples.
Many testimonies, albeit fragmentary, of Greek-Roman Naples still survive, incorporated in the buildings of the modern city, notably the Theater, whose remains are clearly visible in some houses in Via Anticaglia; stretches of the city walls at Largo S. Aniello a Caponapoli, Via Costantinopoli, Piazza Bellini, Via Foria, Via Mezzocannone, Piazza Calenda; the layout "per strigas" of the ancient city (still reflected in the regular street plan of the historical center of Naples) and the subterranean remains of the Macellum and other public buildings still visible under the convent of S. Lorenzo Maggiore in Piazza S. Gaetano, in the area of the civic and religious center both of the Greek and the Roman city, where the agorà or forum lay, as well as a temple dedicated to the Dioscuri, later to become the Capitolium, under the church of S. Paolo Maggiore.
Evidence of the Roman age expansion of the city can be found both to the west (the public baths, which have been included in the tour of the newly instituted Museo dell'Opera di S. Chiara), and to the east (the building remains under the Dome and the thermal facilities of Vico Carminiello ai Mannesi). The expansion of the city towards the north and the exploitation of the coast for seaside tourism is documented by the villa of Vedius Pollio (Pausylipon) on the promontory of Posillipo (under which the gallery called "Crypta Neapolitana" runs), the public baths of Via Terracina and those of Agnano.