Horse collar from the Tres Riches Heures du Duc de Berry c. 1412
Technology and innovation don't have to be flashy. Often times it is the most mundane of things that have the greatest impact. Take the adoption of the horse collar harness. A change in the way horses are harnessed for work helped usher in an agricultural revolution.
Domestication of the horse is believed to have occurred in the Central Asian steppes near present-day Kazakhstan in the third millennium BCE (Before Common Era).
The use of the horse quickly expanded to the Near East and Europe with the development of chariot-warfare. For much of this early period, horses were used primarily for riding or for pulling lightweight chariots. There seemed to be a lack of utilitarian use of the horse such as for plowing or pulling heavy loads. Factoring into this underutilization was the design of harnesses employed at the time.
The throat-girth design was the first widespread harness system used for horses. Adapted from the yoke, the throat-girth harness is depicted in the artwork of Sumeria, Egypt, Greece, and Rome. In its simplest form, it consisted of flat straps across the neck and chest with the load attached to the top above the neck.
Whenever the horse pulled, the straps pressed against the horse's chest and windpipe. This restricted the animal's ability to breathe. The harder it pulled, the harder it became to breathe. Due to this physical limitation, oxen were the preferred animal to do heavy work such as plowing. Yet oxen are not efficient draught animals. They are hard to maneuver, are slow, and lack the endurance of horses. Agricultural production became limited.
The Romans understood the limitations of horse and harness. They limited the weight of loads that could be transported over Roman roads. Yet for all their practical problem-solving prowess, the Romans did very little to improve upon the harness they clearly saw as inadequate. It would be the Chinese who would make the first attempt at modifying the throat-girth harness.
Sometime in the second century BCE, the Chinese developed the breast-strap or breast collar harness. It became widespread during the Han Dynasty (202 BCE - 220 CE), and by the 7th century CE (Common Era) it had become used throughout Central Asia. The breast-strap harness would eventually appear in Europe during the 8th century CE.
The breast-strap was an additional part of the harness whose purpose was to prevent the harness from slipping backward. This was intended to relieve the pressure off the horse's neck and windpipe. The problem, though, with these designs, was that the shafts or traces of a vehicle were attached to a surcingle - the strap that went around the belly of the horse. This resulted in the animal literally pulling a load - the least effective means of doing work. The harnesses did not take full advantage of the horse's true power and strength.
The breakthrough came once more in China. This was the invention of the horse collar during the 5th century CE. The horse collar was designed as an oval and fitted around the neck and shoulders of the horse. It generally was padded to conform to the shape of the body but left the airway of the horse free from constriction.
This slight change was monumental. It achieved two major goals. First, it relieved the pressure off of the horse's windpipe. Second, the traces could be attached to the sides of the collar. This allowed the horse to push forward with its more powerful hindlegs rather than pulling with the weaker front legs. This meant horses were now able to pull heavier loads.
One of the first people to demonstrate the increase in efficiency between the throat-girth and the horse collar was a French cavalry officer Lefebrve des Noettes. His experiments in 1910 showed that two horses using the older system of harness were able to pull 1/2 ton load. Meanwhile, a single horse, using the horse collar, was able to pull 1 1/2 tons of load. Scholars have questioned Lefebrve's findings. More recently, archeologists have argued that there were intermediate designs that worked well at preventing the constriction of a horse's breathing. Ancient art and artifacts show the possible use of partial yokes or breast collars that were rigid enough to keep the harness from riding up a horse's neck. These harnesses would work just as well as the horse collar at allowing the horse to pull heavier loads. The true advantage of the horse collar was that the traces could be set lower on the horse - an ideal position for plowing.
Regardless, the impact of the horse collar was significant. With its introduction in Europe around 1000 CE, it meant a shift away from oxen as the main farm draught animal. A horse can do twice as much work as an ox in less time. With the horse collar, farmers could take full advantage of a horse's strength. The horse was able to pull another recent innovation, the heavy plow. This became particularly important in areas where the soil was hard and clay-like. This opened up new territories to agriculture. The horse collar, the heavy plow, and horseshoes helped usher in a period of increased agricultural production. Between 1000 CE and 1300 CE, it is estimated that crop yields increased by threefold. This lead to a population explosion in Europe which was cut short by the arrival of the plague in the mid-1300s.
Not all inventions arrive with a splash or with fanfare. Born out of necessity, the mundane horse collar quietly transformed agriculture and in turn transformed the world.
Further Reading
The Shorter Science and Civilization in China Vol. 1 and Vol 2 : Joseph Needham (Abridged version edited by Colin Ronan)
Early Harness Systems : Jean Spruytte
Science and Technology in Medieval european Life : Jeffery Wigelsworth