Bronze statuette of the Gallo-Roman age (I-II century A.D.), representing the goddess Arduinna riding on a boar, now in the National Archaeological Museum (Musée d’Archéologie Nationale), Saint-Germain-en-Laye, near Paris, France.
Divinity of the continental Celts, Arduinna was a goddess of the woodlands and of the wild animals, who the Romans identified with their goddess Diana or with the Greek Artemis. She is frequently represented riding a boar, running across the forests of the Ardennes, which took their name from the goddess. The hunters who ventured into her territory could kill their prey only if they let in exchange some offerings to Arduinna, who was a true “Lady of the animals” and, in some measure, identified herself with the beasts of the woodland. Her name contains probably the root ard-, meaning “hill, plateau”. This figure can be compared with the Irish goddess Flidais, who ruled over the animals of the forest and whose cattle was made up by wild deer.
Some Germanic gods had also a strict relationship with the boar. Freyja was described sometimes as accompanied by a gilded boar, called Hildisvíni (“Battle Pig”), perhaps one of her devotees transformed into an animal. The pigs were sacred to the goddess, and one of her names was Sýr (“Sow”). Her brother, Freyr, was also described riding the boar Gullinborsti (“Gold-bristle”) or Slídrugtanni (“Dangerous Tooth”), and to this god pigs were often sacrificed. The boar was thus strictly associated with the Germanic deities of fertility, the Vanir (Lindow 2001).

[Image: http://www.suppressedhistories.net/secrethistory/gaelsgauls.html]