George Peppard dropped out because he didn't get on with director Cy Endfield. He insisted that Endfield be replaced, but Stanley Baker, who was co-producing the film with Endfield (his close friend) replaced Peppard instead.
The film didn't do well in theaters but since became a cult film.
The film was shot on location in the Kalahari Desert, with studio work done at Shepperton Studios in London.
Producer/star Stanley Baker had wanted Lee J. Cobb for the part eventually played by Theodore Bikel.
After Richard Burton and Elizabeth Taylor demanded too much money, star/producer Stanley Baker pursued Robert Mitchum and Carroll Baker as the leads. After these negotiations failed, he signed George Peppard, who left abruptly after a short time. Stuart Whitman was quickly drafted in, but he didn't like the part so he swapped roles with Baker.