The Hellenic tribes were Greek ancestors. They migrated southward into the Balkan peninsula in several waves, roughly 2000 BC. These tribes were four Indo-European tribes known as the Hellenics. They were the Achaeans, Dorians, Ionians, and Aeolians. In the fifth century BC, Dorians and Ionians were the two most politically important Greek ethnic groups, whose ultimate clash resulted in the Peloponnesian War.
The Dorians: The Dorians are best known for their invasion of mainland Greece which, along with the civil war at the end of the Mycenean, led to the Greek Dark Ages. The Dorians were the most pugnacious people of the four Hellenic tribes. They originated from north/northwestern Greece, Macedonia and Epirus. From these points they began to invade toward the south, into the center of mainland Greece, then to the Peloponnesian and the southern Aegean islands.
The Ionians: The Ionians were a people who migrated from western Anatolia, Attica and other Greek territories directly following the Dorian immigration into mainland Greece (roughly 1,000 BC). Militaristically, they were considered by the vast majority of Greek society (from 450 BC onward) to be soft compared to the Dorians and other Greek militaristic factions. The Ionians ruled parts of Euboea, Attica, most of the islands of the Aegean Sea, as well as the western coast of Asia Minor. Many of its cities were instrumental in setting up trade routes with such places as the Black Sea. From a cultural perspective, the Ionians added a great deal to classical Greece.
The Aeolians: The name comes from the fact that they were considered to be descended from Aeolus (whose father Hellen was the mythological patriarch of all Hellenes). Originating in Thessaly, they moved their location when the Dorians were attacking the Achaeans and then abandoned most of the Mycenaean territories. The Aeolians took over some of the abandoned territory and built few cities on islands near Asia Minor. They began building these cities well after the Mycenaeans were defeated, and gave rise to the Aeolian dialect of the Greek language.