Prince Frederick Charles Alexander of Prussia (German: Friedrich Karl Alexander; 29 June 1801 – 21 January 1883) was a younger son of Frederick William III of Prussia. He served as a Prussian general for much of his adult life and became the first Herrenmeister (Grand Master) of the Order of Saint John after its restoration as a chivalric order.
Issue. Frederick William II of Prussia (1744–1797) . married (1) Elisabeth Christine of Brunswick-Lüneburg.They had one child Princess Frederica Charlotte of Prussia (1767–1820), who married Prince Frederick, Duke of York and Albany, the second son of George III of the United Kingdom.