Gangloffsömmern near Weissensee in Thuringia was the oldest property of the Counts of Brühl. Parts of the estate were already owned by the family in 1479. The site was in the Thuringian district of the Electorate of Saxony. In 1738, Count Heinrich von Brühl and his siblings sold the manor to Duke Johann Adolph II of Saxony-Weissenfels.
When the line of Saxony-Weissenfels died out in 1746 and all their property fell to Electoral Saxony, Augustus III gave the ancestral seat of the Brühls to his prime minister. After the death of the prime minister, Pförten and Gangloffsömmern were combined and were to be passed on undivided within the family. The owners lived in Pförten, while the manor of Gangloffsömmern was only important as an economic subsidiary. The manor house was demolished in 1846 to make place for new farm buildings. The 1945 Land Reform led to the dissolution of the estate.
Today: There are no remaining traces of the von Brühl family in Gangloffsömmern.