In 695 Seaxburh decided to translate the remains of her sister Æthelthryth (who had been dead for sixteen years) from a common grave to the new church at Ely in a vivid demonstration of the dynastic value of the cult of royal saints in Anglo-Saxon England, Professor Patrick Sims-Williams has identified Seaxburh as "the chief mover behind the translation of her body and the promulagation of her cult". The "Liber Eliensis" describes these events in detail. When her grave was opened, Æthelthryth's body was discovered to be uncorrupted and her coffin and clothes proved to possess miraculous powers. A sarcophagus made of white marble was taken from the Roman ruins at Grantchester, which was found to be the right fit for Æthelthryth.