In antiquity, several theses were elaborated on the origin of the Etruscans from the 5th century BC, when the Etruscan civilization had been already established for several centuries in its territories, that can be summarized into three main hypotheses. The first is the autochthonous development in situ out of the Villanovan culture, as claimed by the Greek historian Dionysius of Halicarnassus who described the Etruscans as indigenous people who had always lived in Etruria. The second is a migration from the Aegean sea, as claimed by two Greek historians: Herodotus, who described them as a group of immigrants from Lydia in Anatolia, and Hellanicus of Lesbos who claimed that the Tyrrhenians were the Pelasgians originally from Thessaly, Greece, who entered Italy at the head of the Adriatic s