Ark of the Covenant
The container of the Tablets of the Law in the Old Testament. It has been suggested that it was identical with the Grail. Its fate is something of a mystery. Boren and Boren say Joseph of Arimathea may have brought the Ark to Britain.
When Graham Hancock discovered that the Virgin Mary had been allegorically identified with both the Grail and the Ark on occasion, the suspicion dawned on him that they might both be the same thing.