Complex sentence: Little is known about his episcopate, but he was held to be a saint after his death, with a saint's life being written long after his death when his relics were moved from his original burial place to a new burial spot in 1091.
Split into simpler sentences: Little is known about his episcopate, but he was held to be a saint after his death. A saint's life was written when his relics were moved from his original burial place to a new burial spot in 1091.