When the Poles invaded the Tsardom of Russia in 1605, a self-identified prince, known as False Dmitry I, assumed the Russian throne. A Polonophile, he assured that King Sigismund III of Poland could control the country's internal and external affairs, secure Russia's conversion to Catholicism and thus make it a puppet state. Dmitry's murder was a possible justification for arranging a full-scale invasion by Sigismund in 1609. The Seven Boyars deposed reigning Tsar Boris Godunov to demonstrate their support for the Polish cause. Godunov was transported as a prisoner to Poland, where he died. In 1610, the Boyars elected Sigismund's underage son Władysław as the new Tsar of Russia, but he was never crowned. This period was known as the Time of Troubles, a major part in Russian history that remains relatively unmentioned in Polish historiography because of its implied Polonization policies.