The Collar and the Plow

An ox and a horse are harnessed differently because they are built differently. An ox pulls from its shoulders against a wooden yoke, which sits on a frame the animal already has. A horse has no such frame, and early European harness ran a strap across the animal's chest and windpipe. The horse was faster and stronger, and it could not be used for heavy plowing, because pulling hard closed its airway.

The rigid collar, which reached Europe from Asia, moved the load to the shoulders and left the throat free. The horse could now deliver its power for hours. What followed was less a change in farming equipment than a change in the unit of work available to a village: a team that moved faster over the same ground, needed fewer animals for the same field, and could be harnessed and unharnessed quickly.

Historians differ about how much should be credited to the collar alone. Iron plowshares, the horseshoe and a shift to three-field rotation all belong to the same centuries, and each one made the others worth having. The safest statement is the narrow one: the collar removed a limit, and what was done with the freedom it created depended on tools and arrangements that had to arrive as well.