Heimskringla Sacrifice

King Haraldr had earlier sent word to Jarl Hákon, while the king was stationed
on Mársey, that the jarl should come to his assistance. The jarl had then
arrived at the island after the king had had himself baptised. Then the king
sends word that the jarl should come to meet with him. And when they met
each other, then the king forced the jarl to have himself baptised. Then Jarl
Hákon was baptised and all the men who were with him. Then the king
provided him with priests and other clerics and says that the jarl must have
all the people in Norway baptised. Then they parted. Jarl Hákon goes out
to sea and there waits for a favourable wind. And when the wind comes
that he thought would carry him out to sea, then he shoved all the clerics
up ashore, and then he himself sailed out to sea, and the wind was blowing
to the south west and west. The jarl then sails east through Eyrarsund. He
makes raids then on both shores. After that he sails east past Skáneyjarsund
and raided there too, wherever he came to land. And when he came east
off Gautasker, then he sailed to land. Then he performed a great pagan
sacrifice. Then two ravens came flying there, screeching loudly. Then the
jarl felt sure that Óðinn had accepted the sacrifice and now it would be a
propitious time for the jarl to fight. Then the jarl burned all his ships and
went up inland with his troops and ravaged everywhere. Then Jarl Óttarr
came against him. He was ruling over Gautland. They had a great battle
with each other. Jarl Hákon wins the victory there, but Jarl Óttarr fell
and a large part of his force with him. Jarl Hákon goes across both parts
of Gautland and ravages everywhere, until he comes to Norway, going
after that by land all the way north to Þrándheimr. It tells about this in
Vellekla:

125. On the field the felling-Njǫrðr of
flight consulted oracles;
Heðinn’s attire’s tree-trunk
took the war-Sága’s chosen day.
And strong vultures of slaughter
he saw, the battle-offerer.
The blood-bowl Týr then wanted
to break off lives of Gautar.

126. The jarl, where no man earlier
under Sǫrli’s dwelling
had harried, held the meeting
of hollow-of-swords’ burning;
None brought rounds wrapped in
resting-place of the heather-
whale further from the water; the ruler
went over all Gautland.

127. The god of Fróði’s storm stacked
slaughter on the battlefield;
the gods’ kinsman could glory
in gain; the slain went to Óðinn.
Who doubts the disrupter of royal
race by gods is guided?
I say the splendid deities
strengthen Hokon’s power


- Heimskringla, Óláfs saga Tryggvasonar, Chapter 27