Feodosia Morozova was a 17th-century Russian noblewoman and a prominent leader within the Old Believer movement. Born into the Sokovnin family in Moscow, she married the wealthy boyar Gleb Morozov and later served as a lady-in-waiting at the tsarist court. Following the religious reforms of Patriarch Nikon, she became a staunch defender of traditional practices. Her refusal to accept these changes led to her arrest and eventual death in a prison cell, where she is remembered as a martyr for her faith.