Goofs

Ludwig II told Otto von Bismarck that he wished they could be friends but couldn't due to different assignments. However in real life they were pen pals and wrote each other, despite only met each other once.

Otto von Bismarck never visited Ludwig II as a king, he only visited him in person as a prince in 1863.

The famous painting of King Ludwig II with the sward and in blue clothes and fur by Gabriel Schachinger was finished in 1887, after Ludwig's death. In the movie it is visible finished in a scene set in 1884.

When being in the Opera Ludwig II told Sophia after they are engaged that they are watching Wagner's "Rhinegold". That opera premiered in 1869 while the engagement was in 1867.

After the German war ended in 1866 there is a Reichsflag hanging outside of the palace's window. The German Reich didn't exist until 1871 and the Reichs Flag was not in use until that year and being official only in 1892. The Prussian flag should have been hanging instead, as they were the ones, who won the war.