The term in its various meanings gives its name to the Middle High German heroic epic the Nibelungenlied.
The most widespread use of Nibelung is used to denote the Burgundian royal house, also known as the Gibichungs (German) or Gjúkingar (Old Norse).
The earliest probable surviving mention of the name is in the Latin poem Waltharius, believed to have been composed around the year 920.
In lines 555–6 of that poem Walter, seeing Guntharius (Gunther) and his men approaching says (in the Chronicon Novaliciense text, usually taken to be the oldest): Nōn assunt Avarēs hīc, sed Francī Nivilōnēs, cultōrēs regiōnis.
In the eddic poem (see Poetic Edda) Atlakviða, the word Niflungar is applied three times to the treasure (arfr) or hoard (hodd) of Gunnar (the Norse counterpart of German Gunther).
The variant form Hniflungr also occurs as the name of Högni's son in the eddic poem Atlamál, and as a term for the children born by Gunnar's sister Gudrún (Guðrún) to Atli (Attila the Hun).
There are confusions and doublings in the Þiðrekssaga and it may be that Aldrian was properly the name of Hǫgni's elf father.
Their sister Grímhild bore to Atli (Attila) a son named Aldrian who is slain by Hǫgni.
At the end of the resultant battle, Hǫgni, though mortally wounded, fathered a son on Herad, one of Þiðrek's relations.
This son, named Aldrian, accomplished Atli's death and became Jarl of Niflungaland under Brynhild (Brynhildr).
These family relationships might seem to prohibit any elvish siring, but in the cognate story of Brân the Blessed in Branwen ferch Llŷr, Hagen's counterpart Efnisien had a brother named Nisien who was similarly his opposite and Efnisien and Nisien are maternal half-brothers to Brân and Manawyddan just as in the Þiðrekssaga, Hǫgni was maternal brother to Gunnar and Gernoz.
A younger brother named Gutthorm (Gutþormr) take on the role of Sigurd's slayer, after being egged on by Gunnar and Högni in the eddic poems Brot af Sigurðarkviðu (stanza 4), in Sigurðarkviða hin skamma (stanzas 20–23), and in the Völsunga saga (as well as being mentioned in the eddic poems Grípisspá and Guðrúnarkviða II).
According to the eddic poem Hyndluljóð, stanza 27: Gunnarr ok Högni, Gjúka arfar, ok it sama Guðrún, systir þeira; eigi var Gutþormr Gjúka ættar, þó var hann bróðir beggja þeira; allt er þat ætt þín, Óttarr heimski.
If Gotthorm or Gutthorm, the slayer of Sigurd in northern tradition, is brother of Gunnar and Högni, but is not a son of Gjúki, he must be a maternal half-brother, just as Hagen, the slayer of Siegfried in the German tradition, is a maternal half-brother in the Thidreks saga.
In the eddic poems Guðrúnarhvöt and Hamðismál, Erp (Erpr), a third son of Jónakr, was born by a different mother.
The Atlamál (stanza 28) brings in two sons of Högni by his wife Kostbera, named Snævar (Snævarr) and Sólar (Sólarr).
In this way, Siegfried gained the Nibelung treasure, though he still had to fight the dwarf Alberich, whom he defeated and made guardian of the hoard.
In a later poem Das Lied vom Hürnen Seyfrid ('The Song of Horny-skinned Siegfried'), known only from 16th century printed versions, the original owner of the hoard is a dwarf named Nibeling (or Nyblung).
At Worms Siegfried met King Gybich, his three sons Gunther, Hagen, and Gyrnot, and his daughter Kriemhild.
The German versions of the tale make much of Kriemhild's right to the "Nibelungen" treasure through her previous marriage to Siegfried.
Some seemingly took Nibelung to apply primarily to Siegfried's treasure, in which case it must mean something else than the Burgundian royal family, and so another explanation was contrived.
In "Silver Fir Cones", one of the tales found in Otmar's Volkssagen (Traditions of the Harz) (Bremen, 1800), the king of the dwarfs is named Gübich.
In the 19th century, the dwarf theory was popular and was adopted by Richard Wagner for his operatic Ring cycle which was very freely adapted from the tales surrounding Siegfried and the Burgundians.
[4][5][6][7] Heusler reasoned that the name became attached to the various possessors of the Nibelungs' treasure and thereby passed from the mythical beings, to Siegfried, and then to the Burgundians in the Nibelungenlied.
[3] George Gillespie presents the theory that the name Nibelung originally applied to the Nibelungid cadet branch of the Pippinid dynasty of Frankish mayors of the palace, the later Carolingian emperors.
[13] Gillespie and C. W. von Sydow argue the name may derive from Nivelles in Walloon Brabant, where the Pippinids founded a monastery and maintained strong connections.
[15] Ursula Dronke and Helmmut Rosenfeld argue that the name Nibelung originally referred to a Burgundian clan.
They note the existence of several place names in Savoy, the location of the French kingdom of Burgundy, which can be derived from a reconstructed Nibilungos, including Neblens, Noblens, and Neublans.
[18] Rosenfeld, on the other hand, argues that the Burgundian clan name Nibelung was adopted by the Nibelungid cadet branch of the Frankish Pippinid dynasty once Charles Martell's brother Childebrand I and his descendants came to rule the former Burgundian kingdom as counts.
[17] Dronke subscribes to the traditional scholarly derivation of the name Nibelung from nibel or nebel, meaning cloud or darkness.