During the Neolithic the region was inhabited by Iberian related peoples, who also lived in other regions of Atlantic Europe at the time. They built religious monuments called megaliths. Dolmens and Menhirs still survive in the countryside around the city.
The Indo-European Celts invaded after the first millennium BC and intermarried with the Pre-Indo-European population, giving a rise to Celtic-speaking local tribes such as the Cempsi.
Although the first fortifications on Lisbon's hilltop are known to be no older than the 2nd century BC, archaeological research has shown that iron age people have occupied the site since the VIII to VI centuries BC.
The sufix "ippo" (ipo) present in "Olissipo" (the roman name of Lisbon) is characteristic of Tartessos or Turdetani influence. At best Lisbon was an ancient autochthonous settlement (what the Romans called an Oppidum) that maintained commercial relations with the Phoenicians, which accounts for the presence of Phoenician pottery and other material objects.
The gods Aracus, Carneus, Bandiarbariaicus and Coniumbricenses where worshiped at the city by the original Turdulorum Oppida inhabitants.