Many of the scenes were shot in the Carpathian Mountains in Romania, for example, around the city Brasov or in the canyon of Zarnesti.
According to Ray Winstone (interviewed on Desert Island Discs), the horse he rode in this movie was the same horse Russell Crowe rode in Gladiator (2000), and is called George.
According to TIME Magazine, Jude Law had to gain ten kilograms (twenty-two pounds) of muscle for his role on-location in Romania. As there wasn't any regular fitness equipment around, he did so by carrying his personal trainer around on his back, dragging logs, and pushing a tennis-court roller.