the importance of the Crown. Due to the Thirty Years War, mercenaries were common, so he hired English and Scottish officers to modernize the army, helping to push Russia into the modern age. Issue Filaret's marriage to Xenia Shestova produced six children, of whom two survived into adulthood: Tatyana (d. 1612), married Prince Ivan Mikhailovich Katyrev-Rostovsky, no issue Boris (b. 1592, died in infancy) Nikita (b. 1593, died in infancy) Michael (1596-1645), first tsar of Russia from the House of Romanov Lev (b. 1597, died in infancy) Ivan (b. 1599, died in infancy) References Sources Sebag Montefiore, Simon. The Romanovs: 1613 to 1918. (Penguin Random House, 2016) 1553 births 1633 deaths 16th-century Russian clergy 17th-century Russian clergy Metropolitans and Patriarchs of Moscow House of Romanov 16th-century Eastern Orthodox bishops 17th-century Eastern Orthodox bishops Married Eastern Orthodoxy clergy