The Ionians were one of the four main ancient Greek ethno-linguistic groups, linked by their use of the Ionic dialect of the Greek language. The other three groups were the Dorians, the Achaeans and the Aeolians. They were known collectively as Hellenes. The Athenians, in the peninsula of Attica, were the only Ionians on the Greek mainland. The Greeks of the Aegean islands, however, were almost entirely Ionian, the main exception being the Aeolians of Lesbos and the Dorians of Rhodes. The northern shores of the Aegean, in Thrace, were also home to Greek colonists of Ionian descent and the French city of Marseilles was founded by Ionians.
The middle section of the Greek-speaking western coast of Asia Minor was actually called "Ionian" and its inhabitants so outshone the other Asian Greeks, the southern Dorians and northern Aeolians, that Asians used the term "Ionian" (Assyrian "Yamanni," Medieval Muslim "Yunan" to refer to all Greeks. This is still the case - Greece/Greek is Yunanistan/Yunanlı in Turkish, Yunan/Yunani in Arabic.
According to semi-historical Greek legend, Ionia was colonised by refugees from mainland Greece expelled by the invading Dorians in the Heroic Age, leaving Attica as the only European outpost of the Ionian race. According to myth, the Ionians were descended from the hero Ion, son of Xouthus, son of Hellen (the mythical progenitor of all the Hellenes, whose other two sons were Aeolus and Dorus).
The etymology of the word is uncertain. Its Mycenaean Greek reconstruction is Iawones (pronounced Yawones), a name that seems to have been in general use; that is, "Athenians," "Chians," "Chalcidians," "Mytileneans" and so on, are more local names adopted by the original Iawones. Most derivations postulate that it evolved into Greek from some preceding name, either Indo-European or Pelasgian (pre-Greek).