The Hellenic tribes, at the beginning of the seventh century before Christ, were divided into four groups,--the Achaians, Æolians, Dorians, and Ionians,--with outlying tribes more or less akin. But this Hellenic people had been preceded in Greece by another race known as Pelasgians. It is so difficult to say who these were, that Mr. Grote, in despair, pronounces them unknowable, and relinquishes the problem. Some facts concerning them may, however, be considered as established. Their existence in Greece is pronounced by Thirwall to be "the first unquestionable fact in Greek history." Homer speaks (Iliad, II. 681) of "Pelasgian Argos," and of "spear-skilled Pelasgians," "noble Pelasgians," "Pelasgians inhabiting fertile Larissa" (II. 840; X. 429). Herodotus frequently speaks of the Pelasgians. He says that the Dorians were a Hellenic nation, the Ionians were Pelasgic; he does not profess to know what language the Pelasgians used, but says that those who in his time inhabited Crestona, Placia, and other regions, spoke a barbarous language, and that the people of Attica were formerly Pelasgic. He mentions the Pelasgians as remaining to his time in Arcadia, after the Dorians had expelled them from the rest of the Peloponnesus; says that the Samothracians adopted the mysteries of the Kabiri from the Pelasgians; that the Pelasgians sacrificed victims to unknown gods at Dodona, and asked that oracle advice about what names they should give their gods. These names, taken from Egypt, the Grecians received from them. Hellas was formerly called Pelasgia. The Athenians expelled the Pelasgians from Attica (whether justly or unjustly, Herodotus does not undertake to say), where they were living under Mount Hymettus; whereupon the Pelasgians of Lemnos, in revenge, carried off a number of Athenian women, and afterward murdered them; as an expiation of which crime they were finally commanded by the oracle at Delphi to surrender that island to Miltiades and the Athenians. Herodotus repeatedly informs us that nearly the whole Ionian race were formerly called Pelasgians.[207]