The trifunctional hypothesis of prehistoric Proto-Indo-European society postulates a tripartite ideology ("idéologie tripartite") reflected in the existence of three classes or castes—priests, warriors, and commoners (farmers or tradesmen)—corresponding to the three functions of the sacral, the martial and the economic, respectively. The trifunctional thesis is primarily associated with the French mythographer Georges Dumézil, who proposed it in 1929 in the book Flamen-Brahman, and later in Mitra-Varuna. Three-way division According to Georges Dumézil (1898–1986), Proto-Indo-European society had three main groups, corresponding to three distinct functions: Sovereignty, which fell into two distinct and complementary sub-parts: one formal, juridical and priestly but worldly; the other powerful, unpredictable and priestly but rooted in the supernatural world. Military, connected with force, the military and war. Productivity, herding, farming and crafts; ruled by the other two. In the Proto-Indo-European mythology, each social group had its own god or family of gods to represent it and the function of the god or gods matched the function of the group. Many such divisions occur in the history of Indo-European societies: Southern Russia: Bernard Sergent associates the Indo-European language family with certain archaeological cultures in Southern Russia and reconstructs an Indo-European religion based upon the tripartite functions. Early Germanic society: the supposed division between the king, nobility and regular freemen in early Germanic society. Norse mythology: Odin (sovereignty), Týr (law and justice), the Vanir (fertility). Odin has been interpreted as a death-god and connected to cremations, and has also been associated with ecstatic practices. Classical Greece: the three divisions of the ideal society as described by Socrates in Plato's The Republic. Bernard Sergent examined the trifunctional hypothesis in Greek epic, lyric and dramatic poetry. India: the three Hindu castes, the Brahmins or priests; the Kshatriya, the warriors and military; and the Vaishya, the agriculturalists, cattle rearers and traders. The Shudra, a fourth Indian caste, is a peasant or serf. Researchers believe that Indo-European-speakers entered India in the Late Bronze Age, mixed with local Indus Valley civilisation populations and may have established a caste system, with themselves primarily in higher castes. Reception Supporters of the hypothesis include scholars such as Émile Benveniste, Bernard Sergent and Iaroslav Lebedynsky, the last of whom concludes that "the basic idea seems proven in a convincing way". The hypothesis was embraced outside the field of Indo-European studies by some mythographers, anthropologists and historians such as Mircea Eliade, Claude Lévi-Strauss, Marshall Sahlins, Rodney Needham, Jean-Pierre Vernant