The time in which the Grail romances were developing was similar to our own in some respects. Many people were searching for spiritual fulfillment outside official church channels. This was especially true in the Languedoc region of France, where a "heretical" movement, known as the Albigensians or Cathars, similar to the Gnostics from the beginnings of Christianity, grew until it was violently suppressed by the Catholic Church in the early 13th century.

Some scholars have speculated that the imagery of the Grail quest may have been influenced by the spiritual struggles of these unorthodox believers as well as earlier Pagan and Christian sources. The Celts had legends of a cauldron in which the dead could be brought back to life. In addition, there was a Christian legend that Joseph of Arimathea had sealed up a container with Christ's blood and, in obedience to divine command, had released it on the ocean. Where it came ashore, according to the legend, a church was built where miracles took place. This latter legend bears a striking resemblance to the earlier Egyptian myth of Osiris' sarcophagus being sent out on the waves.

Whatever it may have been, the Grail always had the dual nature of life and death. On the one hand, it was a type of traveling reliquary, containing Christ's shed blood (and sometimes his body as well). On the other, it was said to bestow live-giving food of any sort wished for, and, more importantly, to fulfill one who found it with spiritual life.

Sometimes, the Grail was depicted as an emerald cup or a stone. It is possible that the Albigensians could have been familiar with, and inspired by, the "Emerald Tablet of Hermes," a short text that outlined the "Hermetic Dictum": "As above, so below."

In any case, the Grail has only grown over the centuries as a symbol of the elusive nature of spiritual enlightenment.