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.