When giving his wife Czaress Elisabeth her medicine Aleksey Razumovski said "It will help" by saying the Russian word "Pomogaet". Howeverit means "It helps" (present form). "It will help" would be "Eto pomozhet".
During the entire movie Prussia is shown as a single fighter against France, Austria and Russia. However in real life they were supported by Portugal, Great Britain and also other German Regions including Hessen-Kassel, Schaumburg-Lippe or Saxony-Gotha-Altenburg.
When King Frederic II asked von Treskow about his sister Wilhemine of Bayreuth's messages, he said that she doesn't send any messages anymore, referring to her recent death. The scene is set in 1760, as the conquest of Berlin by the Russians was mentioned. However Wilhelmine was already dead in 1758.
The Austrian emblem that was shown in the movie, set in 1760 was not used until the 19th century. The emblem of Empress Maria Theresia that was used at that time showed the double-head-eagle with only one crown while not holding the sword and Globus cruciger. Also it had all emblems of the Austrian regions all together on its body underneath two separate crowns.
King Frederic II is constantly announced as "King of Prussia". This title didn't exist until 1772 after he conquered Polish-Prussia, Ermsland and other Eastern regions that gave him ownership for "both Prussias". Until then the title for him and others before him was "King IN Prussia".