Wikipedia, the free on-line Encyclopedia says of Horse Brasses:-

Types of horse brass have been in existence since before the 12th century in England. They were introduced as decorations but soon became used as good luck and status symbols. By the 18th century and even before they were used as a talisman to ward off the "Evil Eye" or stay free of the devil's hand. The most popular size is 3 x 3 1/2 inches of flat brass with a hanger hole on top to be threaded onto a horse harness strap, or 1 to 8 mounted on a 4 inch wide leather strap known as a martingale and put on a harness or mounted on the local pub wall. Wagons and carts were also decorated with brasses of all kinds and sizes. European Gypsies seem to be credited with adding bells to the brasses to help with warding off the "evil Eye". By the mid 1800s farmers used horse brasses looking like sun and moons to help conger up a good growing season. Other brasses had likenesses of pixies carrying lanterns in the farm fields thus coming to American folklore as "Jack-o-'lantern" at pumpkin carving fame. All the royals starting with Queen Victoria, but maybe before, had special brasses made for their carriages and horses. Merit awards given by the Royal Society for Prevention of Cruelty to Animals (RSPCA) of horse brasses were prized by the "carters" delivering freight all over England by horse cart. Other horse brass subjects include advertisers, souvenirs for places and parades and events and are still being made and used today.

Please visit my other E-bay auctions and E-bay Store where I have several other horse brasses and items from England. I am always happy to combine shipping costs when making multiple purchases.