Curiosidades

When interviewed on set in 1977, director Pier Carpi angrily denied that his screenplay was inspired by O Exorcista (1973) and pointed out to the interviewer that he merely adapted his own novel "Un ombra nell'ombra" which he claimed to have written in the sixties but which, in fact, was published first in 1974. However, it is assumed that Carpi's original cut of the movie was considered too much unlike "The Exorcist" by the producers who thus ordered extensive re-cutting and re-shoots.

Filming began in 1977, stopped because of lack of funds an completed in early 1979.

This film was only partly shot by Pier Carpi. Several scenes were in fact filmed by producer Piero Amati, including the opening ballet of the witches. Amati explained: "In the contract that I had with...the financier, it was written that I had to shoot these scenes. And so, I filmed this footage of black masses and things like that...He had written it as a 'conditio sine qua non'. But thy turned out to be crap..."

Victoria Zinny was to be in the film, but she left during shooting, after refusing to deliver the following line, initially not included in the script: "Abortion is a monstrous idea. The governments that allow it are composed of criminals."

American actor John Phillip Law was dubbed by Ted Rusoff in the English version.