Tyr is a relatively minor Aesir god in Viking Age Norse mythology. However, his name and attributes along with evidence from the study of comparative religion divulge to us that his Viking Age form is a severely diminished version of a divine figure who, in earlier ages, was the highest god of the Norse and other Germanic peoples. By the Viking Age, this role had been usurped by Odin.
While mentions of Tyr in Old Norse literature are few, he certainly seems to have been regarded as one of the principal war gods of the Norse, along with Odin and Thor. For example, in the Sigrdrífumál, one of the Eddic poems, the valkyrie Sigrdrífa instructs the human hero Sigurðr to invoke Tyr for victory in battle. Another poem, the Lokasenna, corroborates this picture by having Loki taunt that Tyr could only stir people to strife, and could never reconcile them.
It is also mentioned that Tyr lost one of his hands to the wolf Fenrir. Tyr’s one-handed-ness seems to be one of his defining attributes. The only full explanation of this handicap comes from the Prose Edda, which recounts how, when the gods endeavored to bind Fenrir for their own safety, the wolf refused to allow the suspiciously innocent-looking cord to be put around him unless one of the deities put his or her hand in his mouth as a pledge of good faith. Only Tyr was brave and honorable enough to comply with the beast’s request, and, when Fenrir found himself unable to break free of his fetters, he accordingly helped himself to the god’s hand.
The tale of the loss of his hand suggests that Tyr was appealed to not only in matters of war but also in matters involving law, justice, honor, oaths, and upholding traditional sources of authority.