Holy Lance
The Holy Lance, also known as The Spear of Longinus and the Spear of Destiny, was an important Christian relic dating from the First Crusade.
According to the gospel of John in the Christian Bible, after Christ was crucified, a Roman centurion by the name of Longinus pierced the side of the body to prove it was dead, producing a rush of "blood and water." The spear, thus covered in the blood of Christ, would be a potent relic -- perhaps the most potent relic in medieval Christian belief after the True Cross.
The Holy Lance was "discovered" (or, perhaps, rediscovered) in 1098CE by a peasant, Peter Bartholomew, during the First Crusade siege of Antioch. He claimed to have been told by God in a vision that the Lance was under the floor of the cathedral in Antioch; when the paving stones were pulled up the fragments of a spear were found, and it was acclaimed as the spear mentioned in the Bible. Thus fortified with a powerful relic, the flagging morale of the Crusaders was restored and a great battle was fought against the besieging Turks, breaking the siege and establishing Antioch as a Crusader stronghold.
The fate of the Lance carried in the First Crusade is unknown, but fragments of spears purporting to be the Holy Lance abounded in medieval Europe, including several complete spearheads.