Holy Lance
The Holy Lance, also known as the Lance of Longinus (named after Saint Longinus), the Spear of Destiny, or the Holy Spear, according to the Gospel of John, is the lance that pierced the side of Jesus as he hung on the cross.
Fisher King
The more recent writings have the lance presented in the Fisher King's castle with Christian theology. More specifically, it is supposed to be the lance that pierced Jesus Christ while on the cross. This is seen in Malory's "Le Morte d'Arthur". In Malory's version the Fisher King is healed with the blood from the lance, signifying it as a good, holy, Christian object. In "Corbenic" we see the precession at the Fisher King's feast, featuring heavily on the Holy Grail, which is a strong Christian artifact. It can be extrapolated that in the same precession, the accompanying lance is the lance that pierced Jesus Christ.