Just finished season two! I like the show a lot. I am totally ignorant to that history, so I have no clue how true to what really happened the show really is. To be honest, I like it better not knowing what ultimately happens.
One minor aspect of the show that I loved was the priest secretly transcribing all the Roman writings for the King. I have read up on Ancient Rome and the Roman Empire a bunch, and know that most everything I've read and what's available to people now are very educated guesses - as all primary evidence of what transpired was lost during the fall and over the course of time. I've always been fascinated by the 'what if' of maybe it's all somewhere buried.