This was the first Ealing Studios movie to be shot in colour.
The real Philip Christoph Von Königsmark was attacked and abducted by the Elector's men. He disappeared and, according to the confessions of his alleged assassins many years after the event, his body was weighted and dropped into the River Leine.
The story of the romance between Sophia Dorothea and Philip Christoph von Königsmark was based largely on a series of love letters published in "The Love of an Uncrowned Queen" (1900), which may or may not be forgeries.
A scene featuring Jewish moneylenders was cut due to the anti-Semitic riots in the U.K. in 1947.
While shooting screen tests as a stand-in for Stewart Granger, Sir Christopher Lee actually got a part in this movie, but the scene was cut out, presumably because both actors looked too much alike.