Anna of Russia
In 1730, Ferdinand, then 75 years old, married young Johanna Magdalene of Saxe-Weissenfels. That same year, Anna of Russia became tsarina of the Russian Empire. The Council of the Duchy finally recognized Ferdinand as duke. However, in 1736, the King of Poland, August III, in a private meeting, offered the throne of Courland to Ernst Johann von Biron. Biron was Anna's lover and had great influence on state affairs.