Vanir (The Spear of Destiny)
From Tardis Wiki, the free Doctor Who reference
The Vanir were a tribe of Vikings in 141, influenced by the Master under the alias of Frey to fight Odin and Thor and the Third Doctor so that he could get Grungnir, the Spear of Destiny. The Doctor explained to Jo Grant that Norse mythology probably came from real adventures of early Viking history, as here the fight between Vanir and Odins folk, in the Sweden of the year 141. (PROSE: The Spear of Destiny)