The Holy Nail, brought to Trier by Empress St. Helena in the 4th century. This iron spike, said to be one of the four with which Christ was nailed to the cross, was a highly important relic in medieval Trier. It was carried in processions, used for swearing oaths, and is reported to have healed several blind people during one of its exhibitions. It was stored in St. Andrew's Altar and is now displayed alongside it in the Treasury. The reliquary made to hold the nail dates from c.980.