Grail Quest - another twist in the trail

In my book The Wonderful History of the Sword in the Stone I put forward the theory that the Christian version of the book was perhaps written by St Dyfrig but I now think I may have been mistaken.  In my last blog I mentioned the fact that the role of 'Keeper of the Book' was hereditary and in assuming that for monks this meant it passed from spiritual father to spiritual son I traced it back through Saints Illtud and Cadoc to Dyfrig.  However further research has revealed that Cadoc and Illtud were not of the School of Dyfrig as I had assumed.  Cadoc was tutored from the age of seven by Tathan (St Athan), an Irish contemporary of Dyfrig and so was of his school at St Athans, Glamorgan or Swent near Chepstow.  Illtud was trained by Cadoc and so is a scholar of his school at Llancarfan.  Applying the hereditary principle therefore it would seem that the originator of the Christian version of The Sword in the Stone was Tathan rather than Dyfrig.  He is also of the right age and location to fit the profile of the Christian writer. Having said that since there is no firm evidence to link the book to either of them directly any identification must remain speculative.