William was the youngest son of the Count Palatine
John Charles of Gelnhausen (1638–1704) from his second marriage, Esther Maria (1665–1725), a daughter of George Frederick, Baron Witzleben of Elgersburg. William served from 1729 in the Austrian army and was wounded during the
Battle of Mollwitz. In 1742, he won a victory against the French general Bouffleur and drove the French from Tein. In 1743, he became
General of the Cavalry in the Dutch army. In 1754, he accompanied Emperor
Francis I to his coronation in
Frankfurt. In the same year, he became imperial field marshal. In 1757 he was appointed
governor of
Namur. == References ==