Personally, I think one of the most difficult judgment calls in writing historical fiction is the handling of names and place names, especially when dealing with time periods where written resources are scarce. Scandinavia during the Viking Age is one of those times.
Old Norse and Old English are challenging languages for the modern reader. As a writer, I want to be as true to those ancient names as possible. Yet I don't want to bog the reader down. It is a delicate balance. To me, there are few things worse than getting lost in some great passage only to stumble across an ancient word that is difficult to pronounce. Take, for instance, the place name "Þrœndalǫg". It is one of the main settings in GOD'S HAMMER, but how many readers would be able to decipher it? At least most readers can get their tongues around "Trondelag", which is a modern version of that same place.
Then there is the issue of use, or more precisely, which ancient name to use. Different historical resources quite often spell the name of the same person or place differently. Just take the name "Hakon", the main character in GOD'S HAMMER. In ancient texts, his name appears as Hakon, Hacon, Haakon, Hákon, and so forth, depending on the source. Which is more correct?
There is also the problem of exactly when a name appears in history and whether it should be used in a story. "Norway" is a prime example. Scholars are relatively certain that the idea of a single country called "Norway" did not exist in the early 900s. What did exist were smaller kingdoms, or folklands (fylker), that would eventually coalesce into a single country. At what point in history did the word Norway appear in reference to a single country rather than the North Way, a reference to the sailing passage along its western coast? Sometimes, the author must determine whether or not to use names in order to make the story more understandable, even if they are historically inaccurate.
Early on, I decided to adhere to a few rules. First, the name should not tear the reader from the story. Second, it needed to be a close approximation to the ancient name. And third, it needed to be as historically accurate as possible. Hence, Þrœndalǫg became Trondelag, and Hlaðir became Lade. I chose "Hakon" because I wanted his name to be pronounced with a soft "a" and a hard "k". I do not use the name "Norway" even though it would be easier to understand.
I realize that to some readers, adherence to the ancient names is important. My hope is that those readers will find my solutions acceptable nonetheless.