In Norse mythology, Fornjót (Old Norse: Fornjótr) was an ancient giant and king of "Gotlandi, Kænlandi and Finnlandi". His children are Ægir (the ruler of the sea), Logi (fire giant) and Kári (god of wind).
The name has often been interpreted as forn-jótr "ancient giant", and Karl Simrock (1869) because of this identified Fornjotr with the primeval giant Ymir. But it is also possible, as was suggested by Peter Erasmus Müller (1818), that it is one of a well-established group of names or titles of gods in -njótr "user, owner, possessor", which would make Fornjótr the "original owner" (primus occupans vel utens) of Norway.
Fornjót in the texts
How should the wind be periphrased? Thus: call it son of Fornjót, Brother of the Sea and of Fire, Scathe or Ruin or Hound or Wolf of the Wood or of the Sail or of the Rigging.
Thus spake Svein in the Nordrsetu-drápa:
First began to fly
Fornjót's sons ill-shapen.
Fornjót is listed as a giant (jötun) in one of the thulur sometimes included in editions of the Skáldskaparmál. This is as expected, since Fornjót's son Ægir is also identified as a giant in various sources.
In the Orkneyinga saga and in Hversu Noregr byggdist ('How Norway was settled')— both found in the Flatey Book— Fornjót appears as an ancient ruler of Gotlandi. Kænlandi and Finnlandi". He is father of three sons named Ægir or Hlér, Logi and Kári. The Hversu account says further that Ægir ruled over the seas, Logi over fire, and Kári over wind.
Logi appears by that name in Gylfaginning in the tale of Thor and Loki's journey to the castle of the giant Útgarða-Loki in Jötunheimr where Loki was pitted against Logi in an eating contest. The contestants appeared to be equal in speed at eating meat from the bone, but Logi also consumed the bones and even the wooden trencher in which the meat was placed. Útgarða-Loki afterwards explained that Logi was really fire itself.
In the Saga of Thorstein Víking's son
The beginning of Þorsteins saga Víkingssonar ('Saga of Thorstein son of Víking') brings in a king named Logi who ruled the country north of Norway. Logi was the handsomest of men, but with the strength and size of the giants from whom he was descended. (Logi's ancestry is here not otherwise specified.) Because Logi was larger and stronger than any other man in land, his name was lengthened from Logi to Hálogi ('High-Logi') and from that name the country was called Hálogaland 'Hálogi's-land' (modern Hålogaland or Halogaland).
The saga tells that Hálogi's wife was Glöd (Glǫð 'glad'), the daughter of Grím (Grímr) of Grímsgard (Grímsgarðr) in Jötunheim in the far north and her mother was Alvör (Alvǫr) the sister of King Álf the Old ('Álfr hinn gamli') of Álfheim. Or perhaps, the name of Hálogi's wife should be rendered instead as Glód (Glóð 'red-hot embers') if this Logi is indeed either identical or confused with Logi as a personification of fire. The names of his daughters in this account were Eisa 'glowing embers' and Eimyrja 'embers', the fairest women in the land, whose names were later applied to the things which became their meaning, certain indication of the original fiery nature of their father. (Wife and daughters are sometimes wrongly ascribed to Loki rather than Logi in secondary sources.)
Two of Hálogi's jarls named Véseti and Vífil (Vífill) abducted Hálogi's daughters and fled the country. At that point Hálogi is out of the story. Véseti settled in Borgundarhólm (Bornholm) where Eisa bore him two sons named Búi and Sigurd Cape (Sigurðr Kápa). Vífil fled farther east to an island named Vífilsey 'Vífil's Isle' where Eimyrja bore him a son named Víking (Víkingr) who was father of Thorstein (Þorsteinn) the hero of the saga. Víking is made out to be a contemporary of a King Ólaf (Ólafr) who is said to be the brother of King Önund (Ǫnundr) of Sweden. Descendants of Thorstein appear in Fridthjófs saga ins frækna (Friðþjófs saga ins frækna 'Saga of Fridthjof the Bold') and in the Starkad section of Gautreks saga 'Gautrek's saga'.
This account cannot be reconiciled with the account in the Hversu and Orkneyinga saga without assuming multiple figures with the same names. In Thorsteins saga Víkingssonar, Logi (a descendant of giants) is the husband to a niece of King Álf the Old of Álfheim who himself is the husband of Bergdís the daughter of King Raum (Raumr) of Raumaríki. In the other accounts Logi is the brother of Kári who is a distant ancestor of Raum the Old who is father of Álf or Finnálf (Finnálfr), king of Álfheim.
Kári is mentioned in one of the thulur as a term for wind. Otherwise this personage appears only in the Hversu and Orkneyinga saga accounts where Kári appears to be the heir to his father's kingdoms as in the Hversu Kári's descendants emerge also as rulers of "Kænlandi and Finnlandi". Kári is father of a son who is named Frosti ('frost') according to the Orkneyinga saga but named Jökul (jǫkull: 'icicle, ice, glacier') according to the Hversu. This son in turn is the father of Snær the Old (Snærr inn gamli 'Snow the Old').
See Snær to follow this lineage further.
More traditions about persons named Frosti and Logi
In the Ynglinga saga the names Logi and Frosti are otherwise connected when it relates that King Agni of Sweden in a raid on Finland killed Frosti, the leader of the Finns who opposed him and captured Skjálf, Frosti's daughter, and her brother Logi. (But the verse of the Ynglingtal quoted here as confirmation says only that Skjálf is Logi's kin.) For Skjálf's marriage to Agni and her vengeance on him see Agni. Agni himself, as discussed under Snær, is here a descendant of Snær through Snær's daughter Drífa who married King Vanlandi of Sweden.
Fornjót as an ancestor of the House of Yngling
|Yngling family tree|
- Nerthus is often suggested to be the same woman as Njörðr's unidentified sister, by whom he begat Frey and Freyja.
- The Lokasenna and the Skáldskaparmál identify Gymir with Fornjot’s son Ægir, but Rudolf Simek contests this. 
- Assuming Narfi (son of Loki) is identical with Narfi.
- Þornbjörg appears in Gautreks saga and in Hrólfs saga Gautrekssonar.
- Ingeborg appears in the Tyrfing Cycle, e.g. Orvar-Odd's saga and Hervarar saga.
- Áli's inclusion here is based on Beowulf, the oldest source.
- Eanmund is only attested in Beowulf.