From the knights of medieval legends to Indiana Jones, the holy grail has been the most sought-after Christian relic in popular culture for centuries. The grail is most commonly identified as the cup that Jesus drank from at the Last Supper and that Joseph of Arimathea used to collect Jesus’s blood when he was crucified.

Given the importance of Jesus’s crucifixion and the eucharist in Christian beliefs, the search for the grail became the holiest of quests as it signified the pursuit of union with God.

Possibly stemming from the presence of cauldrons and other mystical objects in Celtic mythologies, the grail became a common theme in literature related to King Arthur. French poet Chrétien de Troyes is credited with introducing the grail as a divine object in his early-12th century romance, “Perceval.” Around 1200, Robert de Boron further specified its Christian significance in his poem “Joseph d’Arimathie,” citing the holy grail’s origins at the Last Supper and Christ’s death. While Perceval was the knight destined to pursue the grail in Troyes’s and de Boron’s prose, it was Sir Galahad, introduced in the “Queste del Saint Graal” later in the mid-13th century, who became the most well-known knight of King Arthur’s court to complete the quest.

Although it is generally accepted as mythic, some believe the holy grail is more than just a figment of medieval literature. Some Arthurian tales claimed that Joseph of Arimathea brought the grail to Glastonbury in England. One legend has it that on the spot where he buried the grail, the water runs red because it runs through Christ’s blood, though scientists agree this is just the effect of red iron oxide in the soil. Others believe that the Knights Templar seized the holy grail from Temple Mount during the Crusades and secreted it away.