Famke Janssen was originally signed on for the part of Bathory, but for reasons unknown she backed out. Anna Friel read the script and fell in love with it and sent the director a letter convincing him to cast her. It was written in Slovak language, because her babysitter was from Slovakia and helped her writing it.
Singer Katka Knechtová wrote the title song with lyrics in Old Slavic (Old Church Slavonic language). It is an authentic psalm with only minor modifications.
Error: Near the end of the film, as the Countess speaks with the monk, she lights the five candles at the foot of her bed before putting out the flame. Each time the candles appear again on screen, a different number are lit.