In Celtic mythology Taranis was the god of thunder worshipped essentially in Gaul, the British Isles, but also in the Rhineland and Danube regions amongst others, and mentioned, along with Esus and Toutatis as part of a sacred triad, by the Roman poet Lucan in his epic poem Pharsalia as a Celtic deity to whom human sacrificial offerings were made .[1] He was associated, as was the cyclops Brontes ("thunder") in Greek mythology, with the wheel.

Many representations of a bearded god with a thunderbolt in one hand and a wheel in the other have been recovered from Gaul, where this deity apparently came to be syncretised with Jupiter.[2]

The name as recorded by Lucan is unattested epigraphically, but variants of the name occur in inscriptions, including the forms Tanarus, Taranucno-, Taranuo-, and Taraino-.[3] [4] The name is continued in Irish as Tuireann. His name is likely connected with that of the Germanic god of thunder, Norse Thor (Anglo-Saxon Þunor, German Donar), Tiermes of the Nordic Sami people,[5]

Taranis is likely associated with the Gallic Ambisagrus (likely from Proto-Celtic *ambi-sagros = "about-strength"), and in the interpretatio romana with Mars.

Etymology

The reconstructed Proto-Celtic form of the name is *Toranos "thunder".[6] In present day Welsh taranu and taran means 'to thunder' and 'thunder' (taraniñ and taran in Breton), and in present day Irish Tarann means 'thunder'.

Taranis, as a personification of thunder, is often identified with similar deities found in other Indo-European pantheons. Of these, Thor/Thunor and the Hittite god Tarhun (see also Teshub) contain a comparable *torun- element. The Thracian deity names Zbel-thurdos, Zbel-Thiurdos also contain this element (Thracian thurd(a), "push, crash down").

Association with the wheel

The wheel, more specifically the chariot wheel with eight spokes, was an important symbol in historical Celtic polytheism, apparently associated with a specific god, known as the wheel-god, identified as the sky- sun- or thunder-god, whose name is attested as Taranis by Lucan.[7] Numerous Celtic coins also depict such a wheel. It is thought to correspond to a sun-cult practiced in Bronze Age Europe, the wheel representing the sun.[who?]
The half-wheel shown in the Gundestrup ""broken wheel" panel also has eight visible spokes.

The wheel of the year has eight spokes which connects it to the eight major divisions of the Celtic year. The longest and shortest day and the equinoxes are the four Albans. The other four are Samhain, Brigantia, Beltane and Lugnassadh. These are called the Fire Festivals. The Albans are the oldest, this is why some older wheels only have four spokes.[dubious – discuss]

Symbolic votive wheels were offered at shrines (such as in Alesia), cast in rivers (such as the Seine), buried in tombs or worn as amulets since the Middle Bronze Age.[8] Such "wheel pendants" from the Bronze Age usually had four spokes, and are commonly identified as solar symbols or "sun cross". Artefacts parallel to the Celtic votive wheels or wheel-pendants are the so-called Zierscheiben in a Germanic context. The identification of the Sun with a wheel, or a chariot, has parallels in Germanic, Greek and Vedic mythology (see sun chariot).

From: Wiki
Taranis is in all likelihood the Gaulish god whom Caesar equated with the Roman Jupiter in his writings on the Gallic Wars. The sole mention of Taranis by name in this context is by Lucan, who mentions him as one of three gods to whom human sacrifices were given. Lucan claims that victims were given to each god, killed in a manner appropriate for that god. Victims sacrificed to Taranis were reportedly burned, as would befit a god of lightning and fire. It is often speculated that the Wicker Man sacrifices described by Caesar might have been carried out under the auspices of Taranis.

Taranis is unmistakably a sky god. While he is often pictured riding across the heavens in a great chariot, he is less a god of the sun than a god of thunder. The main emblems of Taranis are his wheel, which he often holds aloft, and a thunderbolt. The name Taranis comes from a root meaning “thunder,” and he is closely related to the Norse god Thor. It was to Taranis that the collected heads of the slain were dedicated.

From: here
Taran
A Brythonic and Gaulish God, also known as Taranis, Taranos, Taranuos, Taranucnus, Taranucus, Taranoou, Etirun: Thunderer

Taran (Taranis, Taranos, Taranuos, Taranucnus, Taranucus, Taranoou, Etirun) is a Gaulish and Brythonic god known from the writings of Julius Caesar, Strabo and Lucan. He is also knowf from eight inscriptions found in Germany, Hungary, Croatia, France and Belgium. He also figures as the character of Taran in the Cymric (Welsh) Mabinogi of Branwen ferch Llŷr. He is the Celtic thunder god, often syncretized with Roman Jupiter.

Synonyms: Taranis, Taranos, Taranuos, Taranucnus, Taranucus, Taranoou, Etirun
Gaul: Thunderer

Taranis standing with thunderbold in his right hand Taranis standing with sky wheel in left hand and thunderbold in right

Taranis is probably one of the most well-known of the Celtic deities, mostly due to the writings of Julius Caesar, Strabo and Lucan; though the actual evidence for this deity indicates that he was far less important than suggested by the Roman commentators. Indeed, outside the work of the classical writers the evidence for this deity is scant at best.

In his De Bello Gallica (On the Gallic Wars) Julius Caesar describes a Gaulish deity whom he likens to Jupiter and of whom he says 'held the empire of the skies'. We are left to Lucan (M. Annaeus Lucanus), however, to name this deity as Taranis. In the first book of his Pharsalia (Civil War) Lucan has this to say about the major Gaulish gods:

Teutates horrensque feris altaribus Esus
et Taranis Scythicae non mitior ara Dianae.

uos quoque, qui fortes animas belloque peremptas

Savage Teutates, Esus’ bloody shrines
and Taranis’ altar, cruel as those
loved by Diana, whom the Scythians serve;
All these destroyed in war…

Based on writings in the ninth century comment on Lucan, the Berne Scholia and descriptions in Caesar's De Bello Gallica Taranis has been identified as the deity to whom both Julius Caesar and Strabo describe human sacrifices being offered by being burnt alive in 'wicker men'. The Berne Scholia also describes Taranis as a 'master of war' and links him with the Roman deity Jupiter. However, these classical sources are all problematic. Caesar (and later Lucan) were both attempting to cast the Gauls in poor light, as a means of justifying the Gallic wars. Which is not to say that the ancient Celts did not perform human sacrifices. The so called 'bog bodies' of Britain and Denmank all attest to the veracity of this claim. However, there is absolutely no archaeological evidence to link the known sites of Taranis worship with cults of human sacrifice. Indeed, Lucan may have been exagerating the importance of Taranis for having never left Rome he had few sources of information about Gaulish deities to draw upon. He therefore had to rely on other Roman writers to gain what information he could.

(...)

Taranis' name is derived from the reconstructed proto-Celtic root *toranos- (Thunder). Thus Taranos' name means 'Thunder' whilst forms such as Taranucnus mean 'Thunderer'. It would seem therefore that Taranis was originally a weather deity, associated with storms and more specifically the thunder and lightning associated with such phenomena. This association with thunder and lightning probably explains his syncretization with Jupiter; though the cult of Jupiter is much broader than what we can discern of the attributes of Taranis. Indeed, Taranis may well represent one of the earliest form of Celtic deities. An elemental force of nature associated with the rumble of thunder. Only after the Roman conquest did he gain a human form and became incorporated into the cult of Jupiter.

Iconographically we have no representation which can be unambiguously attributed to Taranis. Though the so-called 'wheel god' (above right) is often linked to Taranis this identification is by no means certain. Indeed, this linkage is often done on the basis of the lightning bolt in the god's right hand and the description of the wheel in his left hand as the 'thunder wheel'. In all likelihood this wheel could just as easily be a 'solar wheel'. In contrast, the image on the right (which is loosely based on a bronze statue from Strasbourg) shows a man wearing a Gaulish sagum (a heavy woolen coat or cloak) and who simply bears a large thunderbolt in his hand. He has no other attributes and this image would be far more fitting as that of an elemental weather deity with the coat affording protection from the rain (a fertility aspect) that generally accompanies thunderstorms.

From: Celtnet.org (to to link for full article)
Also see:
Article about him