This film was one of the very last 'spaghetti-westerns' to be produced and filmed by a major European studio.
Geoffrey Lewis' voice was dubbed by another actor in the English language version.
It was illegal at the time of the old West to marry your niece or nephew under normal circumstances. However, in one case here in Canada, a marriage between an uncle and niece was upheld because they were of no biological relation to each other; one of them - the niece, presumably - was an adoptee or the uncle married into the family
Italian censorship visa # 71727 delivered on 1 April 1978.
It should be noted that this was the first spaghetti western Giuliano Gemma has dubbed his own voice for the Italian version. The other (reviving) spaghetti western he has done so was Tex et le seigneur des abysses (1985). Previously before these two spaghetti western films, he was primarily dubbed by Pino Locchi.