The branch line of Württemberg-Neuenstadt held responsibility for the town of Neuenstadt am Kocher, Möckmühl and parts of Weinsberg.
Frederick Augustus sided with Brunswick-Lüneburg, joining their regiment as a Rittmeister (a commissioned cavalry officer in charge of a squadron).
Frederick Augustus's father died in March of the same year, leaving his son to take on the business of running the duchy.
As the couple had no surviving male children, Frederick Augustus’s brother, Carl Rudolf, succeeded him as Duke of Württemberg-Neuenstadt.
Historians now believe that premature death was often the result of poor hygiene, spoilt milk and mistakes made during childbirth.