HEIMDAL or HEIMDALL, in Scandinavian mythology, keeper of the gates of Heaven, guardian of the rainbow bridge Bifrost, used by the gods between heaven and earth, son of Odin by nine virgins. He lives in the fort of Himinsbiorg at the end of Bifrost. Nothing can escape his vigilance, for he sleeps less than a bird, sees at night and in his sleep, can hear grass and the wool on a lamb's back grow. With Gjallar (q.v.) he will summon the gods on the day of judgment.