Carl M. Allstrom records in his "Dictionary of Royal Lineage" that
Marfa "The Nun", the mother of Mikhail Romanov, the 1st Romanov
Czar,was the illegitimate daughter of Ivan "The Terrible" and his
mistress Mayvi. too, in the book "Kingdoms of Europe" it says that
"The Nun" Marfa attended the coronation of her teenage son and blessed
him. earlier, the babe Mikhail was given to the Shestov Family to
raise; and Mikhail's father, Fedor [Filaret] Romanov, the Bishop of
Moscow, married Xenia Shestov, who became Mikhail's step-mother.