Douglas Fairbanks Jr.'s father Douglas Fairbanks previously played the title character in Robin Hood (1922).
With David Watson as Robin Hood and Roddy McDowall as Prince John, this was the only time that the two actors who would go on to play Cornelius in the original "Planet of the Apes" saga worked together. McDowall originated the role in the original film, was seen in archive footage from that performance in the prologue of the second film, Beneath the Planet of the Apes (1970), and reprised the character toward an inevitable conclusion in the third movie, Escape from the Planet of the Apes (1971). It was Watson who, when McDowall turned down the role in "Beneath," played Cornelius in a few brief scenes opposite Kim Hunter's Zira and the star of that entry in the series, James Franciscus.