The death of Feodor I of Russia in 1598 caused internal instability and a succession crisis upon the extinction of the Rurik dynasty. Further setbacks that contributed to the escalation of violence was the famine of 1601–1603 which killed two million Russians, around a third of the population. The new Tsar, Boris Godunov, proved to be an ineffective ruler and died after suffering a brain haemorrhage in April 1605. He left one son, Feodor II, who succeeded him and ruled for only a few months, until he and Godunov's widow were murdered under mysterious circumstances in June 1605, possibly on Sigismund's orders. Simultaneously, various impostors and pretenders to the Russian throne appeared claiming to be Dmitry Ivanovich, the youngest son of Ivan the Terrible who in fact died in 1591. After the fall of Sigismund's candidates – False Dmitry I and his Polish wife Marina Mniszech (nicknamed "Marinka the Witch" by the Russians) – Vasili Ivanovich Shuysky was crowned as Vasili IV.