In 'Vikings', there are a number of characters with the title of Earl, which in the Vikings society (as portrayed in the series) is second only in rank to the King. Now, I've seen some criticism of the use of Earl since the Norse word for such a title was Jarl and Earl is an Anglicised version of that title. I think that criticism is silly, since the series is filmed (mostly) in English. They also fight in a shield wall instead of a Skjaldborg, and drink beer instead of bjórr (you get my drift...).
Anyway, there is one exception to this and that is the character 'Jarl Borg'. For this one character, they use the Norse term rather than the English one. I can't see why he is a Jarl while everyone of equivalent title is an Earl?
Does anyone have any insight?