How did the dorian invasion spread greek culture?

The Dorian invasion is a concept devised by historians of Ancient Greece to explain the replacement of pre-classical dialects and traditions in southern Greece by the ones that prevailed in Classical Greece. The latter were named Dorian by the ancient Greek writers, after the Dorians, the historical population that spoke them. Greek legend asserts that the Dorians took possession of the Peloponnesus in an event called the Return of the Hera