This volume collects the work of pioneering Prussian historian Karl Otfried Müller on the origins and religious beliefs of the Dorians, the ancient Greek tribe best known as the ethnicity of the Spartans. According to Müller, it was the Dorians who introduced the worship of the god Apollo to Greece. A new introduction highlights the enduring relevance of Müller's work in relation to modern Paleo-Balkan scholarship, while updating Müller's groundbreaking research on the ancient Greeks and their neighbors.