<p>From the moment Mary, Queen of Scots set foot on English soil in 1568 until her execution at Fotheringhay Castle on 8 February 1587, she was the prisoner of her cousin, Elizabeth I. Unlike Mary's time on the Scottish throne, the dramatic events of these years ? almost half her life ? took place while she was a captive. But while trouble was perpetually simmering beyond her prison walls, within them Mary was constantly plotting. Only towards th...