Dmitry of Uglich
Tsarevich Dmitry or Dmitri Ivanovich , also known as Dmitry of Uglich or Dmitry of Moscow , was a Russian tsarevich famously impersonated by a series of pretenders after the death of his father Ivan the Terrible.
Dmitry was the youngest son of Ivan the Terrible and Ivans only child born to Maria Nagaya. After the death of Ivan IV, Dmitrys older brother, Feodor I, ascended to power. However, the actual ruler of the Russian state was Feodors brotherinlaw, a boyar, Boris Godunov, who had had a claim on the Russian throne. According to a later widespread version, Godunov wanted to get rid of Dmitry, who could have succeeded the throne in light of Feodors childlessness. In 1584, Godunov sent Dmitry, his mother and her brothers into exile to the Tsarevichs appanage city of Uglich. OnMay 1591, Dmitry died from a stab wound, under mysterious circumstances.
Source: Wikipedia