Question: Who is Countess Charlotte Brabantina Of Nassau's maternal grandmother?
Sentence (from "Frederick Augustus, Duke of Nassau"): Friedrich August, Duke of Nassau, Prince of Nassau- Usingen( 23 April 1738 in Usingen – 24 March 1816 in Wiesbaden) was the last Prince of Nassau- Usingen and, jointly with his cousin, Friedrich Wilhelm of Nassau- Weilburg, first Duke of Nassau.
Relevant evidence: No