Like many style staples, the trench coat has its roots firmly in the functional requirements of military apparel. As the name suggests, the coat came to prominence in the trenches of WWI, where it was permitted as a lightweight, waterproof alternative to the traditional officer's coat. Many of its basic components stem from these days: the shoulder straps that were originally used to attach epaulettes, the deep pockets for carrying maps, the rings for holding swords or other equipment and, of course, the classic khaki color scheme.