Frederick August’s marriage resulted in the birth of 14 children of which only three daughters survived. Of Frederick August’s brothers, Ferdinand Wilhelm had already died in 1701 so the Neuenstadt inheritance passed to Carl Rudolf in 1716. Carl Rudolf also became regent for a short time of the main ducal line of Württemberg for the underaged Duke Karl Eugen. When Carl Rudolf died in 1742 the male lineage of Württemberg-Neuenstadt finally disappeared. The only survivors of the duchy, two daughters, lived in Neuenstadt Castle until the line disappeared once and for all with the death of Friederike, at which point Neuenstadt permanently lost its status as a royal residence.