The Frigg and Freyja common origin hypothesis holds that the Old Norse goddesses Frigg and Freyja descend from a common Proto-Germanic figure, as suggested by the numerous similarities found between the two deities. Scholar Stephan Grundy comments that "the problem of whether Frigg or Freyja may have been a single goddess originally is a difficult one, made more so by the scantiness of pre-Viking Age references to Germanic goddesses, and the diverse quality of the sources. The best that can be done is to survey the arguments for and against their identity, and to see how well each can be supported."