Jupiter also a god of war and agriculture, in addition to his political role as guarantor of good faith (public and private) as Iuppiter Lapis and Dius Fidius, respectively. His view is grounded in the sphere of action of the god (who intervenes in battle and influences the harvest through weather). In Georges Dumézil's view, Jovian theology (and that of the equivalent gods in other Indo-European religions) is an evolution from a naturalistic, supreme, celestial god identified with heaven to a sovereign god, a wielder of lightning bolts, master and protector of the community (in other words, of a change from a naturalistic approach to the world of the divine to a socio-political approach). In Vedic religion, Dyaus Pitar remained confined to his distant, removed, passive role and the place of sovereign god was occupied by Varuna and Mitra. In Greek and Roman religion, instead, the homonymous gods *Diou- and Διϝ- evolved into atmospheric deities; by their mastery of thunder and lightning, they expressed themselves and made their will known to the community. In Rome, Jupiter also sent signs to the leaders of the state in the form of auspices in addition to thunder. The art of augury was considered prestigious by ancient Romans; by sending his signs, Jupiter (the sovereign of heaven) communicates his advice to his terrestrial colleague: the king (rex) or his successor magistrates. The encounter between the heavenly and political, legal aspects of the deity are well represented by the prerogatives, privileges, functions and taboos proper to his flamen (the flamen Dialis and his wife, the flaminica Dialis). Dumézil maintains that Jupiter is not himself a god of war and agriculture, although his actions and interest may extend to these spheres of human endeavour. His view is based on the methodological assumption that the chief criterion for studying a god's nature is not to consider his field of action, but the quality, method and features of his action. Consequently, the analysis of the type of action performed by Jupiter in the domains in which he operates indicates that Jupiter is a sovereign god who may act in the field of politics (as well as agriculture and war) in his capacity as such, i.e. in a way and with the features proper to a king. Sovereignty is expressed through the two aspects of absolute, magic power (epitomised and represented by the Vedic god Varuna) and lawful right