Many Norse scholars believe the Vanir were a group of fertility deities who existed in mythology before the original Aesir, perhaps representing an older religious system, much as the Gaia-Uranos family represented an earlier religion in Greece than that of Zeus and the Olympian or as the Irish Firbolg represented an earlier religion than that of the Tuatha de Danaan. The Vanir were fertility gods, more earth-oriented and more concerned with the welfare of humanity than the more warrior-like and patriarchal Aesir. Their most important god was Freyr, the god of fruitfulness and prosperity who descended from the ancient Germanic earth goddess Nerthus. Typically he was depicted with a large phallus, symbolizing human fertility as well as that of nature. His female counterpart and sister was the love goddess Freyja, known for her erotic passions and active sex life. She once sold herself to four dwarfs in exchange for a famous necklace—the necklace of the Brisings.

Freyr and Freyja’s father was the oldest of the Vanir, Njord, associated with the winds and the sea. Another important god who was probably originally a member of the Vanir, was Heimdallr, whom some credit with having created the first man and woman.