A new people invaded Greek territory in force. They were the Dorians, a pastoral people related to the Achaeans who created an internal migratory movement which transposed the locations of the Greek tribes at the end of the 12th century. This new people brought with it a new material, iron, which was of Balkan origin. Iron marked the end of the Mycenaean Age and the transition to the "Geometric Period" in the field of art.

The Dorians came as far down as the Peloponnese. They occupied the entire peninsula with the exception of Arcadia. The Eurotas valley in Laconia became the Doric centre. They were the forefathers of the Spartans. Then there came about a spiritual decline which was followed by the Dark Age of ancient Greece (12th to 8th B.C.).