Belenus (also Belenos, Belinus, Bel, Beli Mawr) is a sun god from Celtic mythology and, in the 3rd century, the patron deity of the Italian city of Aquileia. Called the "Fair Shining One" (or "The Shining God"), he was one of the most ancient and most-widely worshipped Celtic deities and is associated with the ancient fire festival and modern Sabbat, Beltane. He was associated with the horse (as shown by the clay horse figurine offerings at Belenos's Sainte-Sabine shrine in Burgundy) and also the wheel. Perhaps like Apollo, with whom he became identified in the Augustan History, Belenos was thought to ride the Sun across the sky in a horse-drawn chariot.
There are 51 known inscriptions dedicated to Belenus, mainly concentrated in Cisalpine Gaul (Aquileia/Carni), Noricum and Gallia Narbonensis, but also extend far beyond into Celtic Britain and Iberia. Images of Belenus sometimes show him to be accompanied by a female, thought to be the Gaulish deity Belisama.
Tertullian, writing in c. 200 AD, identifies Belenus as the national god of Noricum. Inscriptions dedicated to Belenus are concentrated in the Eastern Alps and Gallia Cisalpina, but there is evidence that the popularity of the god became more widespread in the Roman period. The third-century emperors Diocletian and Maximian each dedicated an inscription to Belenus in the region of Aquileia. A further 6 votive inscriptions of Belenus were discovered at Altinum, Concordia and Iulium Carnicum. The soldiers of Maximinus Thrax, who laid siege to Aquileia in 238, reported seeing an appearance of the god defending the city from the air.
In epigraphy, the forms Belenus, Belinus and Bellenus are on record. Other variants may be corruptions of the same name; thus, a single inscription found near Oulx has Belanus, and Herodian has Belin. The etymology of the name is unclear. Suggestions are informed by the identification with Apollo, but the wide range of attributes of Apollo as the god of light, knowledge, music and poetry, mantic oracles, healing and medicine, etc. opens a wide field of possible parallels. Apollo Karneios with horns from ram (beran) cognates with qeren ("to shine", "have horns") from *qarn. (For l and r relationship see liquid consonant)
The historically favoured interpretation of the name is a "bright/shining one," from a root *bhel "to shine", interpreting Belenus as solar deity in origin (compare the first element in Beltane, from a *belo-te(p)nia "bright fire").
Alternatively, the name may be from a Proto-Celtic *Guelenos, containing a root for "source, well", suggesting identification as a god of healing springs.
Renaissance scholar Pierre Pithou explained the name as deriving from Greek belos "arrow", here taken to refer to the sun's rays, but even in early modern scholarship, the simplistic identification of Apollo/Belenus with the Sun was questioned; Bernard de Montfaucon argued that by the time of the identification of Apollo Belenus, the ancients in their civil worship had long ceased to treat Apollo and Sol as the same deity. Suggestions in early modern scholarship also included a comparison with Semitic Bel, Belus. In this context, linguistically Bel is an East Semitic form cognate with Northwest Semitic Baal with the same meaning; however, the aforementioned similarities can only remain theory, due to how distant the cultures in question are.
Yet another suggestion (by Schrijver 1999) suggests a connection with henbane, known as belenuntia, bellinuncium, bellenium in antiquity (surviving in Spanish beleño). This herb contains the deliriant drug scopolamine. This plant would have been extensively used by the druids of the tribes located where the plant grew. The content of the psychoactive experience caused by the plant helps us to understand the origin of the archetype of the god Belenus. Henbane in Latin was known as apollinaris herba ("herb of Apollo").
In ancient Gaul and Britain, Apollo may have been equated with fifteen or more different names and epithets (notably Grannos, Borvo, Maponus, Moritasgus and others).
An epithet of Belenus may have been Vindonnus. Apollo Vindonnus had a temple at Essarois near Châtillon-sur-Seine in Burgundy. The sanctuary was based on a curative spring. Part of the temple pediment survives, bearing an inscription to the god and to the spirit of the springs and, above it, the head of a radiate sun-deity. Many votive objects were brought to the shrine, some of oak, and some of stone. Some offerings take the form of images of hands holding fruit or a cake; others represent the parts of the body requiring a cure. In many cases the pilgrims appear to have suffered from eye afflictions.
In a single inscription, Belenus is given the epithet Teutorix. This is the basis of a suggestion according to which the Germanic name Theodoric was in origin a theonym borrowed from Gaulish into early Germanic religion.
The Welsh given name Llywelyn combines the theonyms Lugus and Belenus.
The name of the ancient British king Cunobelinus may mean "hound of Belinos". Alternatively, in accordance with modern Welsh rendering "Cynfelyn," it could mean "precursor to Belinos," "one who precedes Belinos." A further interpretation based on the kennings (associations of a word in a particular culture) of Cuno and Belinos is "Shining/Excellent Warrior" based on Cuno being Hound or Dog which was associated with Warriors and Bel meaning Shining which has been equated with skill and as such excellence in a particular area e.g. war/ fighting.
Beli Mawr (i.e. "Beli the Great"), an ancestor figure in medieval Welsh literature, has also been connected to the theonym, but alternative suggestions connect the name to Gaulish Bolgios and the tribal name of the Belgae.
Diodorus Siculus named Cornwall (Cornovii, that can originate from "horn") Belerion, the first recorded place name in the British Isles. This is usually derived from the root bel "bright" (meaning "shining land" or similar) and not necessarily connected to the theonym.