This is straight from Wiki: In Norse mythology, a valkyrie (Old Norse valkyrja “chooser of the slain”) is one of a host of female figures that chooses who will win or die in battle. The valkyries bring their chosen who have died bravely in battle to the afterlife hall of the slain, Valhalla, ruled over by the god Odin, where the deceased warriors become Einherjar. There, when the Einherjar are not preparing for the events of Ragnarök, the valkyries look after their tableware and drinks. Valkyries also appear as lovers of human beings and heroes, where they are sometimes described as the daughters of royalty.
An incredibly haunting picture which seems to so perfectly capture the haunting essence of the myth.. click it for a nice big version