Joseph of Arimathea
The story of Jesus visiting Britain as a boy is a late medieval development based on legends connected with Joseph of Arimathea. During the late 12th century, Joseph of Arimathea became connected with the Arthurian cycle, appearing in them as the first keeper of the Holy Grail. This idea first appears in Robert de Boron's "Joseph d'Arimathie", in which Joseph receives the Grail from an apparition of Jesus and sends it with his followers to Britain. This theme is elaborated upon in Boron's sequels and in subsequent Arthurian works penned by others.