False Dmitry I was a figure in early 17th-century Russia who claimed to be the deceased son of Ivan IV, also known as Ivan the Terrible. He emerged during a period of political instability known as the Time of Troubles, which followed the death of Tsar Feodor I. False Dmitry I gained support from various factions, including Polish nobles, and managed to seize Moscow in 1605. His reign was short-lived, as he was overthrown and killed in 1606, leading to further chaos in Russia until the eventual establishment of the Romanov dynasty.