Mark Lester's last acting role. He gave up acting due to the film's poor reception. It was widely rumoured, beginning around 2010, that he would return to acting in a portrayal of King Harold II in a film called "1066". Reports of this project faded toward the end of the 2010s without the film being made.
Rex Harrison deliberately avoided his L'extase et l'agonie (1965) co-star Charlton Heston during filming.
A drunken Oliver Reed brought a prostitute as a gift for Mark Lester to celebrate his birthday on July 11, 1976.
Attempts by Ernest Borgnine to affect a lower class English accent were unsuccessful, so in most scenes, he just played his part with his natural American accented voice, although there are scenes where a bit of an English accent can still be heard.
This movie's failure was largely blamed on the casting of Mark Lester, who, at eighteen, was nine years older than King Edward VI was at the time of his accession to the throne. Lester's performance in the dual title roles was heavily criticized. However, there were also complaints that the movie was "too Americanized".