After Ivan IV, Fyodor I became Tsar but had little interest in ruling. Boris Godunov, brother of Fyodor's wife, ran Russia and fought with Sweden over Estonia. Estonia did not fall, but Russia devastated parts of Finland and gained territory in Karelia.
Fyodor is a simple, pious man and relies on Boris Godunov to administer Russia for him. Godunov does a good job and will seize the throne for himself when childless Fyodor dies.