For the scene where Angelo cried, actor David Sust put toothpaste under the eyes. He shot the scenes so many times that he injured his eyes and had to wear sunglasses for a while.
Director/writer Agustí Villaronga said that the origin of the story came when he read about Giles de Rais (1404-1440), a devoutly religious follower of Joan of Arc who fought valiantly on her side and was later trialed and executed by the Catholic Church for heresy and sexual crimes (sodomy) committed against children, mainly boys, estimates of which range as high as 800.
Günter Meisner originally turned down the role, horrified by the story. According to Villaronga, Meisner called him a few weeks later to accept the part, arguing he couldn't stop thinking about it.
Günter Meisner recited his dialogues phonetically, later it was dubbed by the actor Lluís Homar. Homar was actually 31 years younger than Meisner.