Boris Gudenov was a
nobleman in
Russia and a favorite of
Tsar Ivan the Terrible. Boris got Ivan's son
Fyodor I to marry his
sister Irena, and thus became the Tsar's
brother-in-law when Ivan died and Feodor became Tsar in
1584. Feodor was generally considered feeble-minded, and Boris was the real power behind the
throne. Feodor's younger brother Dmitry died during this period, probably on Boris's orders -- this left Feodor with no heirs. It also left many nobles deeply suspicious of Boris.
When Feodor died in 1598, a council was quickly summoned to decide who would become tsar. Boris was offered the position, as men loyal to him were in some high places. He refused the crown until the (newly elevated from the lower position of Metropolitan, formerly the highest religious rank in Russia) Patriarch of the Russian Orthodox Church gathered a crowd to yell their support for him. (Some historians assume he was responsible for the crowd being assembled.)
Boris tried to make things better for the peasants by forbidding landlords to kidnap peasants from other estates, and allowing the peasants to move from one small estate from another. He supported the Church, also. However, he was pro-Europe at a time when most Russians considered foreigners to be devils. He forced Fyodor Romanov, another possible claimant to the throne, to become a monk (under the name of Philaret) and sent Fyodor's son Mikhail and Fyodor's four brothers into exile. Russia was also struck by famine during his reign.
Ivan's dead son Dmitry came back to haunt Boris. A former retainer for the Romanovs whose real name was Yuri Otrepiev, and had also been a monk under the name Gregory, publicly claimed that he was Dmitry and had escaped attempted murder by Boris. He fled to Poland after first making this claim, and with a lot of Polish support came back to try and kick Boris off the throne. Russian soldiers were reluctant to fight against anyone who even might be a real tsar. During "False Dmitry's" march on Moscow in 1605, Boris suddenly died. His son Fyodor II was proclaimed Tsar, but the invasion forces continued into the country...
Aleksandr Pushkin would write a play about Gudenov in 1825, which would later be made into an opera by Modest Mussorgsky.