"The Holy Grail and the Ark of the Covenant may have been hidden by a secretive religious order of crusaders, the Knights Templar, on the Baltic Sea island of Bornholm some 830 years ago, according to a new book." It's good to see Henry Lincoln is still beating this dead horse. I thought the Grail wasn't really a cup and the ark was at Rennes-le-Chateau. But what do I know? Writes Dean_Paxton at Metafilter:

The grail, of grail legend, in one theory was not either, but a cauldron. Medieval lore is littered with cauldrons other large vessels that are referred to as grails.

These are intended to have magical properties such as rendering unlimited supplies of food, ressurecting the dead, and empowering potions for spells and such.

The first grail legend was written by Chretien de Troyes (1180-1190) that we would associate with our sentiment towards the concept of the holy grail... however, to him Grail was often called Sangreal, which literally means "Holy Grail"... hence, the reference to the sanguine, or blood. In his story, the grail is not a cup, but a large platter or plate....

It is from the french poet Robert de Boron that we get the first description of the grail as a chalice in which Christ took wine at the last supper. Also, in his version... at the crucifixion, Joseph of Arimathea caught the blood of Christ with it.

So, there are an awful lot of ideas about what the grail actually was... we do, however, know it to be a creation of one man's mind... it could be argued that he collected the spoken tradition and put it to words that we now possess, but then again... the entire bible is written based on that construct as well, which is faith. Therefore, I don't feel that this is any more myth than the bible, or other tennant of faith.

The Templars and other groups entered into the picture much, much later (1250-1310)... therefore have been able to create their own interpretations of this myth.