The old metal horseshoes were often made of bronze, wrote Dressage Today, and only had six nail holes. Over time, the shoes had to be made of heavier material. People then started using iron for the horseshoes, despite the metal's high value. So, of course, horseshoes became essential commodities, and people sometimes paid debts in horseshoes rather than coins, which were also made of iron but had less value. During the 12th century, when countries participated in the Crusades, the pile of horseshoes collected for taxes were used in battles.
Superstitions around horseshoes, like nailing them to a wall for luck, also spread. By the 13th century, horseshoes were more readily available, and soon the art of nailing a horseshoe became a profession. Farriers, professional horseshoers, had thriving businesses, as did blacksmiths, who made the shoes. The importance of proper placement and attachment of horseshoes became popular when a book called No Foot, No Horse was written in England in 1751. Specialty horseshoes were also invented and allowed horses to do specific work in trade, transportation, or even battles.
And just like many things during the Industrial Revolution in the 1800s, horseshoes also became mass-produced. Industrialists invented machines that cast shoes on a large scale, with some devices capable of pushing out 60 shoes per hour. American Equus said mass-produced horseshoes even gave the Union Army great advantage during the Civil War as the horses performed better.
