Its only vaguely historical but once you get over that its very enjoyable. Strong female and male roles, a lot of content per episode with a lot of plot twists and turns. Unlike previous reviewer I feel the use of modern language use works well, after all people in british tribal cultures in those days would have been speaking a language we wouldn't understand but to them it would have been the colloquial language of their times. I'm not fond of making something sound archaic when at the time something is set it wouldn't have been archaic at all.
Ending leaves it open for a possible second series and I hope they make one as I will certainly watch it.