There are two groups of gods in Norse mythology the warrior gods known as the Aesir, and the gods of fertility and wealth known as the Vanir or Vana. The Aesir are the warrior gods who first inhabited Asgard, one of the nine worlds. The first three gods of the race of the Aesir were Odin, Vili and Vé. Odin was the father and leader of the Aesir.
In the early days a dispute arose between the Vanir and the Aesir in which they came to arms (see Gullveig). After years of waging war the two groups decided to call a truce when they realized that they could accomplish more together than by fighting each other. Which resulted in the trading of hostages between the races. The Vanir sent Njord his two children, Freyr and Freya, and Kvasir to live in Asgard, while the Aesir sent Vili, Odin's brother, and Mimir to live in Vanaheim.
NOTE: In some places it is noted that Hoenir, not Vili was the 2nd prisoner.
Vili however, was not as smart as the Aesir claimed he was and it was Mimir who gave him advice. The Vanir grew suspicious of the answers Vili gave when Mimir was not around. Eventually they figured out that they had been cheated and they cut Mimir's head off and sent it back to the Aesir. Fortunately, this betrayal did not lead to another war and all the gods of the Vanir were subsequently assimilated with the Aesir.
The Aesir under the leadership of Odin, included Balder (god of beauty), Bragi (god of eloquence), Forseti (god of mediation), Freyr (god of fertility, who originally was from the Vanir), Heimdall (guardian of the bridge), Hod (the blind god), Loki (god of fire and ally of the frost giants), Mimir (the wise god), Njord (the sea god, and another ex-Vanir), Thor (god of thunder), Tyr (god of war), Vili (brother to Odin), Vé (brother to Odin), and Vidar (Odin's son). The goddesses included Freya (the fertility goddess), Frigg (Odin's wife), Sif (Thor's wife), Idun (keeper of the apples of youth), Fjorgynn (weather god), Magni (Thor's son) Modi (Thor's son) Hermod, Nanna (wife of Balder), and Sigyn (wife of Loki).
The names of the horses that the Aesire used were: Sleipnir, Glad, Gyllir, Glaer, Skeidbrimir, Silfrtopp, Sinir, Gils, Falhofnir, Gulltopp and Lettfeti.
Aesir might be derived from the old-Teutonic word Ase, the common word for "god".
Four of the gods were common to the Germanic nations: Odin, chief of the Aesir; Frigg Odin's wife; Tyr the god of war; and Thor the god of thunder. Some of the other important Aesir were Balder, Jord, Heimdall, and Loki.
Old Norse: Æsir
See Also: Vanir