The Holy Grail was an ordinary looking blue cup that had held the blood of Jesus Christ.
According to legend, Joseph of Arimathea brought it to England and buried it. A spring formed after he did this. Only the pure of heart could find it. The knights of King Arthur searched for the Grail, but it was found instead by Godric. Soon after, he was lured into a tree by a dryad. Godric and the Grail remained there for a thousand years, finally released in 1936. The Grail caused pain to anything impure or unnatural. It was used by Harry Sullivan to stop Hester Stanton's magic from turning the land of England itself against its people so her son could become king. The Grail fell into a chasm with Stanton and both were swallowed by the earth. (PROSE: Wolfsbane)
In 1939, the Seventh Doctor asked Heinrich Himmler if he followed the Quest for the Holy Grail. Himmler affirmed that he did. (PROSE: Timewyrm: Exodus)
In 1940, Captain Hartmann experienced a hallucination in which he found the Holy Grail after taking a shot of morphine, following a serious injury in a battle with the Cybermen. (PROSE: Illegal Alien)
The Grail was one of the components of the Sword of Forever. It was discovered centuries later, united with the other pieces and used by Bernice Summerfield. (PROSE: The Sword of Forever)
Miss Foster promoted the Adipose pill as the "Holy Grail of the modern age". (TV: Partners in Crime)