The play, "The Firebrand of Florence," opened on Broadway in New York City, New York, USA on 15 October 1924 and closed in May 1925 after 261 performances. The opening night cast included Nana Bryant as the Duchess, Frank Morgan as Allessandro (same role as in the movie), Edward G. Robinson as Ottaviano and Joseph Schildkraut as Cellini.
"The Screen Guild Theater" broadcast a 30 minute radio adaptation of the movie on May 27, 1946 with Frank Morgan reprising his film role.
According to a 1934 newspaper article, Constance Bennett wore 20 costumes in the film. Weighed together, they amounted to 1,000 pounds of wardrobe; The heaviest of Bennett's costumes was 44 pounds, while the rest averaged about 30.
There really was a Benvenuto Cellini (1500 - 1571) who was a sculptor of great repute from Florence. Not that you'd know it from this film, he was widely thought to be bisexual.
Somewhat erroneously, it was Frank Morgan who was nominated for Best Actor at the Academy Awards, despite his part clearly being a supporting one. This was mainly down to the fact that the supporting actor and actress categories wouldn't come into being for another two years.