Duchess Anna of Prussia died on 1625-08-30.
Duchess Anna of Prussia was born on 1576-07-03.
Duchess Maria Anna Josepha of Bavaria died on 1776-05-07.
Grand Duchess Anna Leopoldovna of Russia died on 1746-03-19.
Grand Duchess Anna Leopoldovna of Russia was born on 1718-12-18.
Duchess Anna Amalia of Brunswick-Wolfenbüttel died on 1807-04-10.
Duchess Anna Amalia of Brunswick-Wolfenbüttel was born on 1739-10-24.
Duchess Maria Anna Josepha of Bavaria was born on 1734-08-07.
Duchess Maria Anna Victoria of Bavaria died on 1690-04-20.
Duchess Maria Anna Victoria of Bavaria was born on 1660-11-28.
She is the widow of a Duke. You address her as Her Grace, in conversation. Eg "Good morning, Your Grace." On introduction, "May I present Her Grace, Dowager Duchess of X" or "May I present Anna, Duchess of X". Obviously, Anna would represent the first name of the Duchess.
Russia