Author Charles K. Hyde wrote: "In many respects, the jeep became "the" iconic vehicle of World War II, with an almost mythological reputation of toughness, durability, and versatility." Not only did it become the workhorse of the American military, as it replaced the use of horses and other draft animals (still heavily used in World War I) in every role, from cavalry units to supply trains, but improvised field modifications also made the jeep capable of just about any other function GIs could think of.