It is an amalgamation of the myth tof Beowa, the slayer of the water-demon and the dragon, with the historical legend of Beowulf, nephew and successor of Hygelac (Chochilaicus), king of the Geatas, who was defeated and slain (c. 520) while ravaging the Frisian coast.
The hero Beowulf comes to the court of Hrothgar from the land of the G6tar, where Hygelac is king.
This Hygelac is undoubtedly to be identified with the Chochilaicus, king of the Danes (really Gotar) who, as mentioned above, made a raid against the Franks c. 520.
The subject of the poem is the exploits of Beowulf, son of Ecgtheow and nephew of Hygelac, king of the " Geatas," i.e.
He is welcomed by Hygelac, and relates to him the story of his adventures, with some details not contained in the former narrative.
The king bestows on him lands and honours, and during the reigns of Hygelac and his son Heardred he is the greatest man in the kingdom.
When seven years old the orphaned Beowulf was adopted by his grandfather king Hrethel, the father of Hygelac, and was regarded by him with as much affection as any of his own sons.
In the disastrous invasion of the land of the Hetware, in which Hygelac was killed, Beowulf killed many of the enemy, amongst them a chieftain of the Hugas, named Daghrefn, apparently the slayer of Hygelac. In the retreat he once more displayed his powers as a swimmer, carrying to his ship the armour of thirty slain enemies.
Now it is related in Beowulf that Hygelac met his death in fighting against the Franks and the Hetware (the Old English form of Attoarii).
The forms of the Danish king's name given by the Frankish historians are corruptions of the name of which the primitive Germanic form was Hugilaikaz, and which by regular phonetic change became in Old English Hygelac, and in Old Norse Hugleikr.
It is true that the invading king is said in the histories to have been a Dane, whereas the Hygelac of Beowulf belonged to the " Geatas" or Gautar.
It is therefore evident that the personality of Hygelac, and the expedition in which, according to Beowulf, he died, belong not to the region of legend or poetic invention, but to that of historic fact.
As the historical character of Hygelac has been proved, it is not unreasonable to accept the authority of the poem for the statement that his nephew Beowulf succeeded Heardred on the throne of the Gautar, and interfered in the dynastic quarrels of the Swedes.
Haethcyn, the son and successor of this Hrethel, is said to have perished in a disastrous battle against the Svear, but his fall was avenged by his brother Hygelac in a subsequent engagement in which the Swedish king Ongentheow was killed.
This Hygelac is clearly identical with that Chochilaicus wrongly described as a Danish king by Gregory of Tours (iii.
The latter fled for protection to the Guar and the war which ensued cost the lives of Eanmund and of Heardred the son and successor of Hygelac. According to the poem Beowulf himself now became king of the Gotar and assisted Eadgils in a campaign which resulted in the death of Onela and the acquisition of the throne by his nephew.