In Norse Mythology, Tyr is the god of war and triumph on one hand, but also appears as the preserver of law and order on the other.
The Old Norse form of the name is the most commonly known and used. Other singular language forms are in Old English Tiw, Tig, Old Dutch dīs and Old High German Ziu, Tiu, Tiuz.
The root of his name suggests that Tyr was originally a father or sky god who was later displaced from that position and declared to be the son of either Odin or Hymir.
In the Interpretatio Romana he is equated with the Roman god of war Mars from the point of view of the Germanic tribes, probably because of the connection between war and law.
Proto-Germanic *teiwaz, Tiwaz, Indo-European *deiwos, means "god" or "divine" and corresponds to Latin divus. In Old Norse (Völuspá), the plural form tívar means "gods" and represents a relic of the basic meaning of teiwaz.
The name and the figure are primitively related to the Indo-European "father and sky god." The Germanic form is thus related to Greek "Zeus" Ζεύς πατήρ (Zeus patér), Roman Jupiter (from Diēspiter, father of heaven), Vedic Old Indian Dyaúh pitá, and Illyrian Δει-πάτυρος (Dei-pátyros).
All these forms can be traced to a word *dyews 'sky' and 'day', which can be taken to mean "appearance" or "radiation". From this is derived *deywo- > ancient Indian 'deva', Latin 'deus', etc. This connection of the names is still found in Baltic mythology, where Dievs appears as the supreme sky god.
Tiwaz is believed to have been the original chief god in Germanic Central Europe until the Migration Period. The French religious scholar Georges Dumézil (1898-1986) has pointed out, among other things, the structural parallels to the figure of Scaevola in the ancient Roman heroic saga.
There is also a similarity to the Irish Nuada with the "silver hand". However, the similarity is limited to the loss of a hand or an arm under fundamentally different circumstances in each case.
A part of the research believes, the archaic Germanic society understood itself in its structure as of divine origin. One thesis sees the bipartite top Tiwaz/Tyr - Wodan/Odin, analogous to the Indian god figures Mitra - Varuna, as characteristic for the Indo-European god system.
Otto Höfler and Karl Helm assume that Tiwaz was displaced by Wodan as the main god.
This shift of emphasis of the religious cult is said to be caused by a spreading of the cult of Wodan from the Lower Rhenish Northwest Germany. This view, however, is still an open question of dispute in research today.
Also inner-Germanic changes, for example the unification and formation of large tribes like the Saxons and Franks could have contributed to it.
Tiwaz/Tyr is sovereign of law. With Odin, however, a dynamic, ecstatic figure would emerge, who is endowed with the highest creative power and, among other things, works magically, by blinding the opponents and provides advantages over Tiwaz/Tyr in warlike combat. In contrast, Tiwaz/Tyr remains relatively statically the guardian of the law and protector of the Thing assembly.
Tacitus mentioned in the Germania Mars beside Hercules and Mercury as Germanic gods, furthermore in his annals that with the Teutons Mars was main god "praecipuus deorum Mars".
The older research, based on Snorri Sturluson, interpreted here Mars mostly as Tyr because of the naming of the weekdays, but because of Nordic and Indo-Germanic parallels also Freyr can be mentioned.
As late as the 6th century in Norway, sacrifices were made to Tiuz above all other gods (human and animal sacrifices), and he was worshipped as the supreme god.
The structural proximity and connections of the two god figures to each other and the dynamic social upheavals within Germanic societies then led to a reconstruction of the North Germanic pantheon in the 9th and 10th centuries, which is reflected in the high medieval written collections of the Edda, in which the original image of Tiwaz is only partially, but still recognizable.
Tyr is strongly limited in power in the north and fades away, nevertheless all essential qualities of Tiwaz appear. According to the Eddic writings of the Song-Edda, the giant Hymir is named as father of Tyr, but deviating from this, in the Prose-Edda Odin is named as such. There is no tradition concerning Tyr's mother.
He was considered the protector of the Thing, the tribal assembly. His symbol is the sword, with which he throws himself into the battle. In order to be able to bind the wolf Fenrir with the magical bond Gleipnir, Tyr feels compelled to hold his own hand in the mouth of the dangerous wolf as a pledge.
However, when the wolf realizes that the gods want to keep him bound, he bites off Tyr's hand, and the latter must henceforth fight with his left hand. In the Ragnarok, Tyr kills Garm, the hound of hell, but he himself dies.