The superstition of the four-leaf clover is thought to originate with the Druids. Apparently they believed the shamrock helped them to see evil spirits, thereby allowing them time to get away or find a safe hide-out. The four-leaf clover was also used to ward off evil as it provided a magical repellent that would turn away bad luck. The bearer of the clover was also able to see fairies and this became a very popular past-time with children in the middle ages. Young adventurers would go out each day to find four-leaf clovers and once they found them, would then proceed to look for fairies among the flowers and fields.
The three-leaf clover is also associated with good luck as it is believed to be a symbol for the Holy Trinity. By wearing a three- or a four-leaf clover, good luck is brought to the bearer.