1640 establishments in the Holy Roman Empire

Saxe-Eisenach () was an Ernestine duchy ruled by the Saxon House of Wettin. The state intermittently existed at three different times in the Thuringian region of the Holy Roman Empire. The chief town and capital of all three duchies was Eisenach.

Saxe-Gotha () was one of the Saxon duchies held by the Ernestine branch of the Wettin dynasty in the former Landgraviate of Thuringia. The ducal residence was erected at Gotha.