Cameron Mitchell's voice is dubbed by another actor in the English-language version.
Roberto Nicolosi's score was released on CD by Digitmovies in 2007. Although announced as the "complete" 58-minute score, the dance number for the Kessler twins is mysteriously missing. One possible explanation is that the music the Kesslers are dancing to is strikingly similar to alternate composer Les Baxter's love theme from La fosa y el péndulo (1961).
After the British Board of Film Censors passed it with an "A" certificate on 17 April 1963, distributors Compton-Cameo immediately sent the film out on the Essoldo circuit (as Fury of the Vikings) with a UK premiere in Newcastle-upon-Tyne on 21 April 1963. A surprising decision by Compton was to co-bill this Italian epic about Vikings with "X" rated melodrama That Kind of Girl (1963) which warned of the dangers of venereal disease. Nevertheless, the two films had a fair number of pre-London showings together before reaching the Essoldo, Chelsea on 18 August 1963. Compton didn't manage to secure a release on the major circuits, but the double bill still received a large number of bookings.