 Though the Romans had developed an iron "hipposandal" that resembled a hoof boot, there is much debate over the actual origins of the nailed horseshoe, though it does appear to be of European origin.There is little evidence of nailed-on shoes prior to AD 500 or 600, though there is speculation that the Celtic Gauls were the first to nail on metal horseshoes.The earliest clear written record of iron horseshoes is a reference to "crescent figured irons and their nails" in a list of cavalry equipment from AD 910.