Taranis

Taranis (sometimes Taranus or Tanarus) is a Celtic thunder god attested in literary and epigraphic sources.

The Roman poet Lucan's epic Pharsalia mentions Taranis, Esus, and Teutates as gods to whom the Gauls sacrificed humans. This rare mention of Celtic gods under their native names in a Latin text has been the subject of much comment. Almost as often commented on are the scholia to Lucan's poem (early medieval, but relying on earlier sources) which tell us the nature of these sacrifices: in particular, that the victims of Taranis were burned in a hollow wooden container. This sacrifice has been compared with the wicker man described by Caesar.

These scholia also tell us that Taranis was perhaps either equated by the Romans with Dis Pater, Roman god of the underworld, or Jupiter, Roman god of weather. Scholars have preferred the latter equation to the former, as Taranis is also equated with Jupiter in inscriptions. Both identifications have been studied against Caesar's lapidary remarks about the Gaulish Jupiter and Gaulish Dis Pater.

The equation of Taranis with Jupiter has been reason for some scholars to identify Taranis with the "wheel god" of the Celts. This god, known only from iconographic sources, is depicted with a spoked wheel and the attributes of Jupiter (including a thunderbolt). No direct evidence links Taranis with the wheel god, so other scholars have expressed reservations about this identification.

Various inscriptions attest to Taranis's worship, dating between the 4th century BCE and the 3rd century CE. Scholars have drawn contrary conclusions about the importance of Taranis from the distribution of these inscriptions.

The name Taranis derives from proto-Celtic *torano- ("thunder"), which in turn derives from the proto-Indo-European root *(s)tenh₂- ("to thunder"). Through this proto-Celtic etymon, the theonym is cognate with words for thunder in Old Irish (torann), Old Breton (taran), Middle Welsh (taran), and, as a loanword into a non-Celtic language, the Gascon dialect of French (taram). The Proto-Indo-European s-initial seems to have been retained in Celtiberian steniontes, stenion, and stena.

During the development of Celtic, the word for thunder appears to have undergone a metathesis (transposition of syllables), shifting from *tonaro- to *torano-. For some time, scholars debated whether the Chester altar (154 AD) attests to an unmetathesised form of the god's name, Tanaris. The issue was settled by the discovery of a dedication to Iovi Tanaro ('Jupiter Tanaris') in Dalmatia, which confirms that this form did exist. Ranko Matasović and John T. Koch have also suggested that an old name for the River Po, Tanarus, derives from the unmetathesised form of the god's name. Water of Tanar, a river in Scotland, might also posses a similar etymology.

The association with thunder, suggested by the etymology of Taranis's name, is confirmed by his equation with Jupiter. Taranis's name corresponds etymologically to that of the Germanic god Donar (i.e., Thor). Peter Jackson has conjectured that the theonyms Taranis and Donar (as well as perhaps the epithet Tonans of Jupiter) originated as a result of the "fossilization of an original epithet or epiklesis" of the proto-Indo-European thunder god *Perkʷūnos. Calvert Watkins compared Taranis's name with the name of the Hittite weather god Tarḫunna. However, Koch pointed out that an etymology linking the two theonyms would reverse the order of the metathesis (so that Taranis precedes Tanaris) and therefore compromise the proto-Indo-European etymology.