Wikipedia
Bjarkamál'' (Bjarkemål'' in modern Norwegian and Danish) is an Old Norse poem from around the year 1000. Only a few lines have survived in the Icelandic version, the rest is known from Saxo's version in Latin. The latter consists of 298 hexameters, and tells the tale of Rolf Krake's downfall at Lejre on the isle of Sjælland, described in a dialogue between two of Rolf Krake's twelve berserkers, Bodvar Bjarke (hence the name of the poem), the most famous warrior at the court of the legendary Danish king Rolf Krake, and Hjalte (= hilt). The poem opens with Hjalte waking up his fellow berserkers, having realized they are under attack. In 1030, King Olav had the bard Tormod Kolbrunarskald recite the Bjarkamál to rouse his outnumbered army in the morning before the start of the Battle of Stiklestad, according to Fóstbrœðra saga.
In Bjarkamál, Rolf Krake has subdued the Swedes enough to make them pay him tax. Instead, they destroy his court at Lejre with a trick reminding us of Homer's Trojan horse: The wagons, bringing the valuables to Lejre, are filled with hidden weapons instead. When the Swedes, led by Hjartvar, arrive at Lejre, they are invited to a party, but unlike the Danes, they make sure to stay sober. Saxo has combined motives from the original Danish poem with motives from the second song in the Æneid, known as the nyktomakhi, where Æneas tells Dido about the battle between the Greeks and the Trojans in Troy. The nyktomakhi is of about the same length as Bjarkamál, and containing the same elements: The Trojan horse/the smuggling of Swedish weapons; Danes/Trojans are sound asleep when Swedes/Greeks attack them; plus the climax: The goddess Venus informs Æneas that it is the will of the gods themselves (that is, Jupiter, Juno, Minerva and Neptune) that Troy shall fall, and so he can honourably flee. Correspondingly, Rolf Krake's sister Ruth shows Bjarke the war god Odin, albeit the sight of Odin constitutes the moment when Bjarke and Hjalte die.
A well-known example of the old Norse faith in fylgjur, is Bjarke in Bjarkamál lying fast asleep in the hall, while his fylgja ( doppelgänger in animal shape), the bear, is fighting on his behalf outside. When eventually Bjarke gets up and starts fighting, the bear has disappeared.
The hymn "Sol er oppe" (= Sun is up) from 1817 is Grundtvig's version of the poem.