Cernunnos is a Celtic god associated with sexuality, fertility, the hunt, and the underworld. He was worshipped by the iron age Celts all across Europe as late as the first century CE, and his worship must have begun centuries before that.
Cernunnos is a Romanized name meaning "Horned One." The name is most likely derived from "cornu," the Latin word for horn. The Romans had a habit of changing local names to fit the Roman pattern: most Roman names end in "us." Thus "Cernunnos" was probably the new Romanised name given by the Gauls to all their very old horned gods, in which case its use may have been widespread through out Gaul after it became a Roman province.
The images of Cernunnos are unusually consistent. He is usually portrayed as a mature man with long hair. He is usually bearded, although the most well known image of him on the Gundestrup Cauldron features him clean-shaven. His main attribute is his horns, those of a stag. He wears a torc (an ornate neck-ring worn by the Celts to denote nobility). He often carries other torcs in his hands or hanging from his horns. He is usually portrayed seated and cross-legged, in the meditative or shamanic position.
Cernunnos is nearly always portrayed with animals, in particular the stag. Less often he is associated with other beasts, including bulls, dogs and rats. He is also frequently associated with a unique beast that seems to belong only to him: a serpent with the horns of a ram. The serpent was commonly associated with death and the otherworld, and is hence described as cthonic. Cernunnos carries it in his left hand, and in his right he carries a torc, the Celtic symbol of nobility, the symbol of having been initiated into that special state.
It is frequently mentioned how major a god Cernunnos was in the Celtic pantheon. However, this is based on artwork, not literary sources. There is, in fact, only one known actual mention of Cernunnos in history - his name is inscribed above the head and shoulders of a stag-horned figure from ancient Gaul. The presumption of his widespread cult comes from the multitude of images similar to this monument. The named Gaulish figure is of a balding, bearded, elderly god. Other depictions identified as Cernunnos display a variety of ages.
Lord of the HuntEdit
Always bearing the horns of a stag, Cernunnos is identified with the hunted, which in turn identifies him as hunter as well - shamanistic practices across the world bear witness to the concept that in order to catch your prey, you must identify in spirit with the prey.
God of Sexuality, Fertility, and AbundanceEdit
Stags are sexually aggressive creatures, and the antlers can certainly be considered phallic, marking Cernunnos as a god of fertility and abundance. This aspect is represented in other symbolism as well: cornucopiae, fruit, grain and coins. Don't get Cernunnos mixed up with Pan who is seen with an erected penis in most imagery found of him.
Lord of the UnderworldEdit
Along with knowledge, the serpent is also a frequent symbol of death. The cycle of hunter and hunted of course intimately revolves around death and life from death. As Herne the Hunter, generally considered to be the British Celtic version the same figure, he is the leader of the Wild Hunt.