The Monastery of Glastonbury was reputedly founded by Joseph. Towards 1130, William of Malmesbury writes of a belief that the Old Church was built by disciples of Jesus. While he does not name them, an edition of his work with interpolations and dating from around 1247, does claim that these disciples were led by Joseph. Arriving around 63, they built the church and lived out their days there.
These two roles, of Grail keeper and church founder, are never truly matched in medieval literature. Not one notable writer until Tennyson seems to make the simple statement that Joseph brought the Grail to Glastonbury. Also, while de Boron and the author of Perlesvaus are seemingly aware of the Glastonbury legends, it is not until his establishment as a hero of Grail romance that Joseph makes an appearence in any abbey document. This has often led to the assumption that Joseph was first brought to Britain by European romancers and gradually adopted by the Glastonbury monks and put into their histories. This interpretation has difficulties, however, as some earlier tradition may have filtered into England and France. This material might have Celtic or Welsh origins along with the other Celtic material assimilated by Arthurian legend, possibly giving rise to Joseph's dual role in Arthurian literature. Arthurian scholar Geoffrey Ashe (writing with Norris J. Lacy) says, "The basic question, which neither the Grail cycle nor the Glastonbury story convincingly answers, is why anyone's imagination should have brought Joseph- a most unlikely person- to Britain at all."