After the Romans left Britain in the 5th century AD, marauding Germanic tribes further isolated the Celts in the north and west of Britain, in the Breton areas of France, and in Celtiberian Spain.

However, throughout the 5th century BC playwrights continued to innovate. The playwright Aeschylus added a second speaking role, called the antagonist, and reduced the chorus from 50 to 12.