This is where things get complicated (as is often the way with religion). You don’t just have to describe religious practices. You have to get into the characters’ heads and work out why beliefs make them act and talk as they do.
In this article, Amanda McCrina claims that the vast majority of historical fiction mostly ignores religious practices and the pervasiveness of religion in people’s lives, making them more modern in outlook than they really were. This makes life easier for the modern writer and also makes it easier for the modern reader to identify with the characters.
Miriam Drori, Author 
3 replies on “2015 A to Z Challenge: R is for RELIGION”
Great ‘R’ post. I never would have thought to go in this direction.
Helpful advice.
Trisha Faye
http://www.breadandbutterdays.wordpress.com
http://www.chrysnjay.wordpress.com
http://www.shangriladays.wordpress.com
I had to learn a lot about Orthodox Christianity for my Russian novels. It’s kind of embarrassing how I made a number of unintentional mistakes in the beginning, under the naïve, misinformed assumption that Orthodoxy is like a more old-fashioned, stricter form of Catholicism. The two faiths have some surface similarities, but they’re quite different in some pretty important ways. At least I didn’t get everything wrong, since I did know Orthodox priests are allowed to be married and have children, and that they cross themselves in a different direction.
It’s true, most historical fiction does seem to be more modern in terms of its representation of religion and the impact of it on people’s daily lives.