Thomas, thank you for highlighting the origin of Nascien, the Hermit in Arthurian and Grail tradition. He is an interesting figure!
He is associated with the city (sometimes described as an island) of Sarras, which is where Joseph of Arimathea first took the Grail while conveying it from from Jerusalem to Britain. Joseph of Arimathea’s son Josephus was invested at Sarras as the ‘First Bishop,’ and it is said that from him descended a line of ‘Kings’ who became rulers of Britain.
These ‘bishops’ and ‘kings’ are not the same as those recognised in the outer world where James the Just, brother of Jesus, is generally agreed to have been the first Christian Bishop. My belief is that they represent an Innerworld tradition of Priests of the Grail. Nascien was originally called Seraphe, which means ‘Fiery,’ but after receiving communion from the Grail he changed his name to Nascien, which suggests, perhaps, a ‘stepping down’ into human form. Again, this Grail Communion would not have been the same as the communion offered by Christ at the Last Supper, but something different.
At the end of the story, the Grail was gradually withdrawn from earthly sight and was returned to Sarras on the Ship of Solomon. Nascien, his wife Flegentyne, and Saracynthe the wife of the King of Sarras, all die on the same day. A real Mystery!