Thessaly was the main place of habitaton of the Pelasgi who were not of Greek extraction. This means they were not part of the Hellenic people. Pelasgians did not speak Greek,as per testimony by Herodotus.MOreover, Thessaly did not take its name after number 4,as according to
Dionysius of Halicarnassus, there were 3 main districts in Thessaly after 3 Pelasgians. "The leaders of the colony were Achaeus, Phthius and Pelasgus, the sons of
Larisa and Poseidon"[1.17.1]