Taranis

Taranis 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 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. 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.

Name

Etymology and development

The name Taranis derives from proto-Celtic torano-, which in turn derives from the proto-Indo-European root tenh₂-. Through this proto-Celtic etymon, the theonym is cognate with words for thunder in Old Irish, Old Breton, Middle Welsh, and, as a loanword into a non-Celtic language, the Gascon dialect of French. 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, shifting from tonaro- to torano-. For some time, scholars debated whether the Chester altar attests to an unmetathesised form of the god's name, Tanaris. The issue was settled by the discovery of a dedication to Iovi Tanaro in Dalmatia, which confirms that this form did exist. Ranko Matasović and John T. Koch have also suggested that the Gaulish name for the River Po, Tanarus, derives from the unmetathesised form of the god's name.

Thunder god

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. Peter Jackson has conjectured that the theonyms Taranis and Donar 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 and therefore compromise the proto-Indo-European etymology.

Lucan and the scholia

Lucan

Lucan's Pharsalia or De Bello Civili is an epic poem, begun about 61 CE, on the events of Caesar's civil war. The passage relevant to Taranis occurs in "Gallic excursus", an epic catalogue detailing the rejoicing of the various Gaulish peoples after Caesar removed his legions from Gaul to Italy. The passage thus brings out two themes of Lucan's work, the barbarity of the Gauls and the unpatriotism of Caesar.
The substance of the last few lines is this: unspecified Gauls, who made human sacrifices to their gods Teutates, Esus, and Taranis, were overjoyed by the exit of Caesar's troops from their territory. The reference to "Diana of the Scythians" refers to the human sacrifices demanded by Diana at her temple in Scythian Taurica, well known in antiquity. That Lucan says little about these gods is not surprising. Lucan's aims were poetic, and not historical or ethnographic. The poet never travelled to Gaul and relied on secondary sources for his knowledge of Gaulish religion. When he neglects to add more, this may well reflect the limits of his knowledge.
We have no literary sources prior to Lucan which mention these deities, and the few which mention them after Lucan rely on this passage. The secondary sources on Celtic religion which Lucan relied on in this passage have not come down to us. This passage is one of the very few in classical literature in which Celtic gods are mentioned under their native names, rather than identified with Greek or Roman gods. This departure from classical practice likely had poetic intent: emphasising the barbarity and exoticness the Gauls, whom Caesar had left to their own devices.
Some scholars, such as Jan de Vries, have argued that the three gods mentioned together here formed a divine triad in ancient Gaulish religion. However, there is little other evidence associating these gods with each other. Other scholars, such as Graham Webster, emphasise that Lucan may as well have chosen these deity-names for their scansion and harsh sound.

Scholia

Lucan's Pharsalia was a very popular school text in late antiquity and the medieval period. This created a demand for commentaries and scholia dealing with difficulties in the work, both in grammar and subject matter. The earliest Lucan scholia that have come down to us are the Commenta Bernensia and Adnotationes Super Lucanum, both from manuscripts datable between the 9th and 11th centuries. In spite of their late date, the Commenta and Adnotationes are thought to incorporate very ancient material, some of it now lost; both are known to contain material at least as old as Servius the Grammarian. Also interesting, though less credible, are comments from a Cologne codex, dating to the 11th and 12th centuries. Below are excerpts from these scholia relevant to Taranis:

Commentary	Latin	English
Commenta Bernensia ad Lucan, 1.445	Taranis Ditis pater hoc modo aput eos placatur: in alveo ligneo aliquod homines cremantur.	Taranis Dispater is appeased in this way by them: several people are burned in a wooden tub.
Commenta Bernensia ad Lucan, 1.445	item aliter exinde in aliis invenimus. praesidem bellorum et caelestium deorum maximum Taranin Iovem adsuetum olim humanis placari capitibus, nunc vero gaudere pecorum.	We also find it differently by other . the leader of wars and chief of the heavenly gods, Taranis, to be Jupiter, who was once accustomed to be appeased with human heads, but now to delight in those of animals.
Adnotationes super Lucanum, 1.445.	Taranis Iuppiter dictus a Gallis, qui sanguine litatur humano.	Taranis is called Jupiter by the Gauls, to whom sacrifices are made with human blood.
Glossen ad Lucan, 1.445	Tharanis Iuppiter. hi omnes in Teutonicis partibus colebantur a Taranu. ut feria teutonice dicitur.	Tharanis Jupiter. All of these were worshipped in the Teutonic regions at Taranus, as a day of the week is called in Teutonic.

The first excerpt, about the sacrifice to Taranis, comes from a passage in the Commenta which details the human sacrifices offered each of to the three gods. This passage, which is not paralleled anywhere else in classical literature, has been much the subject of much commentary. It seems to have been preserved in the Commenta by virtue of its author's preference for factual explanation. The Adnotationes, by comparison, tell us nothing about the sacrifices to Esus, Teutates, and Taranis beyond that they were each murderous.
The Commenta tells us that as sacrifices to Taranis, several people were burned in a wooden alveus. The Latin word alveus is translated above as "tub", but it could applied to any hollow container. In various settings, the term could be used to mean a ship's hull, a bath tub, a drainage basin, a canoe, or a beehive. Miranda Green linked this sacrifice with the wicker man, the well-known wooden figure in which the Celts burned humans as sacrifices.
The interpretatio romana of Taranis as Jupiter, given by all three commentaries, is otherwise attested in epigraphy, and agrees with our understanding of Taranis as a thunder god. By contrast, the interpretatio of Taranis as Dis Pater, which only the Commenta gives, is quite obscure. It is not given in any inscription, and we do not know what Taranis had to do with the underworld. Manfred Hainzmann points out that Dis was associated in Latin literature with the night sky and night thunderstorms. Statius, for example, refers to Dis Pater as the "thunderer of the underworld".
In the course of giving the interpretatio of Taranis as Jupiter, the scholiast of the Commenta mentions that Taranis was "leader of wars". This is an unusual trait to associate with Jupiter rather than Mars, though the Romans occasionally gave Jupiter martial functions. Hofeneder has associated the comment that Taranis was "appeased with human heads" with this martial function, as the Celtic custom of carrying off their foes' heads in battle is well-attested. The scholiast describes a transition from human to animal sacrifice, probably connected to the suppression of human sacrifice in Gaul in the Imperial period.
Caesar states in his Commentaries on the Gallic War that the Gauls regarded a Gaulish god as their ancestor. As Taranis is the only Celtic god equated with Dis Pater in ancient literary sources, Taranis has often been a cited as a candidate for Gaulish Dis Pater. On the other hand, Caesar also briefly refers to an unnamed Gaulish god who "rules over all the gods", and whom he equates with Jupiter. It has been suggested that Taranis is behind this description. The similarity between Caesar's description of Gaulish Jupiter, and the Commenta description of Taranis as "chief of the heavenly gods", has been noted, though this may reflect reliance on Caesar's text or a routine characterisation of the Roman god Jupiter.