Voltumna is remembered less for a mythology, almost none survives, than for a place. The Roman scholar Varro calls him the chief god of Etruria, and his sanctuary, the Fanum Voltumnae, was the federal shrine where the twelve peoples of the Etruscan league gathered each year for common council, festival and games. Voltumna thus stood for the political and religious unity of the Etruscan cities, and his sanctuary was the nearest thing they had to a national centre.
The god's own nature is genuinely uncertain: ancient and modern writers have read Voltumna as an earth- or vegetation-god, a god of change and the turning seasons, a chthonic power, or a form of Tinia, and the Romans equated the related Vertumnus, god of the changing year and of gardens, with him. The site of the Fanum, probably near Orvieto, the Etruscan Velzna, was long lost and is still argued over by archaeologists.