Popular screenwriter and producer Michael Hirst says that the spiritual aspects of Vikings is what really drew him in to work on the TV show in the first place, and exploring the rich histories of different religions has always fascinated him.

"It was one of the motivating factors for me writing it! I wouldn't have wanted to write the show without the spiritual aspect. It's something that always interested me," he told Entertainment Weekly in an interview. "The Tudors was about the Reformation, and the destruction of the Catholic faith, and I was deeply interested in that."

Hirst added that paganism is something that he's been interested in for a long time, since there are different aspects to it - there is Roman paganism and Scandinavian paganism, which he considers "richer." The writer said that the sagas tackling paganism are so "bonkers" and compelling, both weird and absolutely wonderful at the same time.

"I'm not making a point particularly, except I'm saying that these people genuinely hold these different beliefs. This is what Christians believed at the time. This is what Scandinavians believed at the time, and very powerfully. I don't think you've ever seen on TV before what pagan practice was. This is the best we know of it," he said.

He said someone told him that Vikings was the only network show bravely tackling religious beliefs, and the writer said that while he cannot speak for the other network shows, he for one takes it very seriously.

"It's part of the fabric of the show. I think it gives the show depth," he said.

Vikings is a historical drama that follows the exploits and adventures of legendary Norse hero Ragnar Lothbrok and his family, and shows his slow and steady rise as an ordinary farmer into a leader.