Different metals and materials will provide horses of different tastes, comfort, and texture in their mouths. Some horses will prefer different types of materials over another. When you see your horse being able to comfortably hold the bit without excessive chewing or evading it means you are on the right path.
Humans and horses have intertwined throughout history, dating as far back as 2600 BC. Using historical evidence, it is believed that the first bits were made out of hemp rope, bones, horns or hardwood.