After his first two starring films, "Captain Blood" and "The Charge of the Light Brigade," Errol Flynn asked Warners to find him a non-swashbuckling role. "Green Light" was the result. However, he was back with sword in hand for his next, "The Prince and the Pauper."
The names of researchers who died trying to track down the source of Rocky Mountain spotted fever, that John relates to Dr. Paige are real.
"Lux Radio Theater" broadcast a 60-minute radio adaptation of the movie on
January 31, 1938 with Errol Flynn reprising his film role.
This film was a hit at the box office, making it the second most popular film for Warner Bros. of the year, behind The Prince and the Pauper (1937).
The "spotted fever" being researched in this film is Rocky Mountain spotted fever. At the time of this picture, the mortality rate of this disease was upwards of 30%. It wasn't until the advent of the antibiotics tetracycline and chloramphenicol in the late 1940's that it could be effectively treated, reducing the mortality rate to under 0.5%.