For hundreds of years, peasants had depended on oxen to pull their plows. Oxen lived on the poorest straw and stubble, so they were easy to keep. Horses needed better food, but a team of horses could plow three times as much as a team of oxen. Before farmers could use horses, a better harness was needed. Sometime before 900, farmers in Europe began using a harness that fitted across the horses chest, enabling it to pull a plow, replacing oxen.
