Next time you tie up your trench coat, remember it came from a muddy trench for generals. The whole point of the length and water resistant fabric was to shield the general from water, not for a fashion statement.
World War I trench coat - Based on heavy serge coats this coat was modified in world war one to include straps, D-rings, and epaulettes. It was used in the trenches and hence called the trench coat. The trench coat was created by Thomas Burberry