I have a whole shelf devoted to Poul Anderson, amazing the range of stories he wrote. Besides Science Fiction some great fantasy/historical fiction. You won't be disappointed reading.
The Broken Sword
-Inspired Michael Moorcock's Elric Series
Thor has broken the sword Tyrfing so that it cannot strike at the roots of Yggdrasil, the tree that binds together earth, heaven and hell. But now the mighty sword is needed again to save the elves in their war against the trolls, and only Scafloc, a human child kidnapped and raised by the elves, can hope to persuade Bolverk the ice giant to make Tyrfing whole again. But Scafloc must also confront his shadow self, Valgard the changeling who has taken his place in the world of men.
Three Hearts and Three Lions
-Inspired Paladins and Trolls in old school D&D, OD&D
Holger Carlsen, wounded in Nazi-occupied Denmark, awakens to find himself in a magical land of knights, dragons, and sorcerers.
War of the Gods
The story of the great King Hadding is one of the darkest and most violent to come down to us from the old North. Hadding was raised by giants far from his rightful throne, as his father, a Danish king, was slain shortly after Hadding's birth. But the time comes when Hadding feels he must reclaim his legitimate place in the land of the old North. He must endure ferocious battles, the charms of voluptuous Valkieries, and a War of the Gods to rival Armageddon.
The Last Viking Series about King Haralad Hardrada
Amazing the history and story of this man!
Invading what is now Yorkshire, Harald Hardrada and Tostig defeated the English earls Edwin of Mercia and Morcar of Northumbria at the Battle of Fulford near York on 20 September. They were in turn defeated and slain by Harold's army five days later at the Battle of Stamford Bridgehttp://en.wikipedia.org/wiki/Harald_III_of_Norway