Oldest Manual of Western Swordsmanship
The oldest surviving manual of western swordsmanship dates back to the fourteenth century and is German in origin. It was written around the 1320s in what is currently modern day Germany. It is a book that may or likely was part of a larger work, the piece contains guidance on the use of a single handed sword.
Sources:
https://en.wikipedia.org/wiki/Royal_Armouries_Ms._I.33
And a Wiki that is a very interesting read:https://en.wikipedia.org/wiki/German_school_of_fencing