Mary, Queen of Scots (1542-1587) sometimes known as Mary Stuart or Mary I of Scotland was Queen of Scotland from 1542 until her forced abdication in 1567.
After fleeing to England and throwing herself on the mercy of her Royal cousin, Queen Elizabeth I she was placed effectively, in Protective Custody for the next 19 years!
Throughout this period she was constantly spied on and, after a time, implicated in a plot against Elizabeth I herself.
By early 1587, Mary was found guilty of treason and, subsequently, executed. Her cousin and rival, Elizabeth I, lived on for another 16 years before dying in 1603.
In a sense though, Mary had her revenge... Her only son, James VI of Scotland eventually became James I of England upon the death Elizabeth who died unmarried and childless.