He was the son of Feodor Nikitich Romanov (later known as Patriarch Filaret) and of Xenia (later known as "the "great nun"" Martha). He was also a first cousin once removed of the last Rurikid Tsar Feodor I through his great-aunt Anastasia Romanovna, who was the mother of Feodor I, and through marriage, a great-nephew in-law with Tsar Ivan IV of Russia. His accession marked the end of the Time of Troubles. During his reign, Russia conquered most of Siberia, largely with the help of the Cossacks and the Stroganov family. Russia had extended to the Pacific Ocean by the end of Michael's reign.