False Dmitriy I

False Dmitry I or Pseudo-Demetrius I (Russian: Лжедмитрий I, romanized: Lzhedmitriy I) reigned as the Tsar of all Russia from 10 June 1605 until his death on 17 May 1606 under the name of Dmitry Ivanovich (Russian: Дмитрий Иванович). Dmitry ascended to the throne after the deposition of Tsar Feodor II and ruled for 11 months before he was assassinated in the 1606 Moscow Uprising and replaced with Vasili Shuisky. Dmitry was a pretender who impersonated Dmitry of Uglich, a son of Ivan the Terrible, and his reign formed part of the Time of Troubles.

He was the first, and most successful, of at least three imposters who claimed during the Time of Troubles to be the youngest son of Ivan the Terrible, tsarevich Dmitry Ivanovich, who supposedly escaped a 1591 assassination attempt when he was eight years old. It is generally believed that the real Dmitry of Uglich died in Uglich in 1591. False Dmitry claimed that his mother, Maria Nagaya, anticipated the assassination attempt ordered by Boris Godunov and helped him escape to a monastery in the Tsardom of Russia, and the assassins killed somebody else instead. He said he fled to the Polish–Lithuanian Commonwealth after he came to the attention of Boris Godunov, who ordered him seized. Many Polish nobles did not believe his story, but nonetheless supported him.

With the support of the Polish–Lithuanian Commonwealth, False Dmitry invaded Russia in 1604 with mixed success, and the war later ended with the sudden death of Tsar Boris Godunov. Disaffected Russian boyars staged a coup against the new tsar, Feodor II. False Dmitry entered Moscow on 21 July 1605, and was crowned tsar. Maria Nagaya accepted him as her son and "confirmed" his story. False Dmitry's reign was marked by his openness to Catholicism and allowing foreigners into Russia. This made him unpopular with the boyars, who staged a successful coup and killed him eleven months after he took the throne. Later, another pretender, False Dmitry II, claimed to be False Dmitry having survived the 1606 Moscow Uprising. His wife of 10 days, Marina, would later "accept" Dmitry II as her fallen husband.

According to historian Chester S. L. Dunning, Dmitry was "the only Tsar ever raised to the throne by means of a military campaign and popular uprisings".