In 'Yorck', Krauss plays an historical personage: General Yorck von Wartenburg of Prussia. During the Franco-Prussian Alliance, King Friedrich Wilhelm ordered all his generals and field marshalls to place their armies at the disposal of Napoleon for the invasion of Russia. (The Prussian king was less interested in helping France than in conquering Russia.) Yorck was the only Prussian commander who defied his king, thereby saving the lives of his men when Napoleon's Russian invasion failed. A statesman as well as a strategist, Yorck negotiates a separate peace between Prussia and Russia.
The military scenes in this film are impressive; director Gustav Ucicky deserves to be better known. Theodor Loos is splendid in a supporting role. The pace of the film is compromised by an unnecessary romantic subplot between Yorck's daughter Barbara (the pallid actress Grete Mosheim) and Yorck's lieutenant (Hans Rehmann). I confess that I'm only vaguely familiar with the history involved here, so I can't tell how much of this movie is factual and how much is fictional. I suspect that the subplot is fictional.
I'll rate 'Yorck' 6 points out of 10, and I commend Werner Krauss's performance.