The following is extracted from http://www.electricscotland.com/history/king_arthur.htm  

A NEW THEORY ABOUT KING ARTHUR   By Kelly d. Whittaker - Author of Knights Templar

Scholars have interpreted the ancient manuscripts that were originally Celtic languages as Old French therefore causing certain words to have different meanings than those languages that were of Old German origins. Bard Taliesin gave a description of Avalon as 'insula pororum Fortunata' which in Old French translates to island of apples. The Bard spoke Celtic which is a form of Old German therefore the description he offered means island by the sea that has profuse vegetation and the inhabitants lived very long lives, in German. King Orry was Guinevere's father. Old French had his name spelt Gorre (Gorray). Gorray would have been the lands in Brittany . Another pronunciation was found by Chretien de Troyes and Marie de France. The two poets stated that Guinevere was from the lands of Gorry-Gorree. This changed the land mass from Brittany to the Isle of Man. This location would explain the strange spelling of Guinevere. Her name was pictish. The Picts were ruling the Isle of Man at the time of Arthur.

This opens a new door or possibly a very old one to the legend of Arthur. Why the Isle of Man and not Glastonbury ? What supporting documents are available on the location of Avalon? The King of Norway, Marie de France and the Perceval manuscripts all coincide with Lancelot's description of his trip to Avalon.

This little island is St. Patrick's island off the west side of the Isle of Man. The ruins of Peel Castle remains even today. This small island was a very important place of worship in the early Catholic Church. So important that the pope actually sent Saint Germanus there in the 5th century. St. Patrick preached there in 444. St. Germanus was there to convert the pagans to Christianity and he did accomplish what he was sent there to do. St. Germanus was also a very fair man, he allowed the Grail ceremony, Easter and All Saints day to be incorporated into the Christian teachings.

Sir John Rhys and other scholars had translated the old languages with supporting documentation that Avalon, the Grail Castle and Arthur's third castle Galoches was indeed on the Isle of Man. Garvase of Tilbury painted King Arthur in a royal establishment, claiming that the palace was in the three-sided, three-legged Island of Sicily . (Scicily also  has the 3 Legs emblem – hence the confusion)

The mystery still remains why the legend was moved to Glastonbury and Wales . A hypothesis is; King Henry II was so obsessed over the predictions of Merlin,  that King Arthur would come back again that Henry actually had the evidence moved to Glastonbury so he could have the Bishops keep a very close watch. When Glastonbury burned, Henry II had it completely rebuilt. It was not completed at his death so Richard the Lion heart finished the task.

The New theory had been fully documented through out the past 1500 years. The information stating that Arthur was a real king, Guinevere being a Celtic Princess, Camelot being a real place and all the other people mentioned as once living and fighting for their beloved religions, exists. The Grail Castle and Avalon has now been translated from old documentation.
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Here's another amazing story that for me adds even more credence to the theories. Click here