This is the complete history of the tractor that changed farming—in America and around the world—forever. International Harvester began to experiment with tractors around 1905. It wasn’t until the early 1920s that the company hit upon a successful model for the small-acreage farmer—and the Farmall tractor was born. The make went on to become the dominant tractor in America, selling more than a million models a year in the peak of the post-war boom.