 In 1191, Empress Constance of the Holy Roman Empire, daughter of Roger
, was captured during her struggle with her nephew Tancred, King of Sicily for the crown of Sicily, and Sicilian Chancellor Matthew d'Ajello wrote to Tancred persuading him to lock Constance in the island Castel dell'Ovo to be better-guarded and secluded from people, and wrote to nobleman Aligerno Cottone in charge of defending Naples ordering him to "ut imperatricem in Castro Salvatoris ad mare benè custodiat" (guard the empress in "Castle of the Savior" (i. e. Castel dell'Ovo) in the sea properly).However, Constance was released the next year and finally became Queen of Sicily.In 1268, King Conradin was imprisoned here before his trial and execution.