Catherine I of Russia
Charles Frederick, then commander of the palace guard in St. Petersburg, attempted to secure his wife's succession to the Russian throne upon the death in 1727 of her mother, the Empress Catherine I of Russia. His attempt failed, but his son by Duchess Anna Petrovna, Charles Peter Ulrich (who - as Duke of Holstein-Gottorp - succeeded in the ducal share of Holstein in 1739), eventually became Russian tsar in 1762, as Peter III.