As a great-granddaughter of Henry VII of England, Mary had once claimed Elizabeth's throne as her own and was considered the legitimate sovereign of England by many English Catholics, including participants in a rebellion known as the Rising of the North. Perceiving Mary as a threat, Elizabeth had her confined in various castles and manor houses in the interior of England. After eighteen-and-a-half years in captivity, Mary was found guilty of plotting to assassinate Elizabeth in 1586 and was beheaded the following year at Fotheringhay Castle. Mary's life and execution established her in popular culture as a romanticised historical character.