Conversation so far:
Is there anything interesting about Erich Ludendorff's Pre-war military career?
In 1885, Erich Ludendorff was commissioned as a subaltern into the 57th Infantry Regiment, then at Wesel.
Where was Erich Ludendorff based after that Wesel with the 57th Infantry Regiment as a subaltern?
Erich Ludendorff was promoted to lieutenant and saw further service in the 2nd Marine Battalion, based at Kiel and Wilhelmshaven.

Question: What was his highest rank?
Self-contained rewrite: What was Erich Ludendorff highest rank?