The film predates Ted Kotcheff's First Blood, the film which introduced audiences to the John Rambo of David Morrell by seven years. Tomas Milian happened to read David Morrell's novel while flying from the U.S. to Rome.
The film came before Ted Kotcheff's First Blood, which first introduced viewers to the character John Rambo created by David Morrell. Tomas Milian happened to come across David Morrell's novel while on a flight from the United States to Rome.