Koppenstein Castle ruin (plan and reconstruction)
Here is the Wikipedia link for the castle. It icludes this interesting paragraph about eh Koppenstein family, "The von Koppenstein family named themselves after the castle . It came from an illegitimate son of Count Johann II von Sponheim-Kreuznach († 1340) (cf. LHAK Best. 700,219 No. 1) and was endowed with important castle and other fiefs by the County of Sponheim. ... The last male bearer of the Koppensteiner name, Jakob Adolf von Koppenstein († 1768), put his closest relative, Damian Freiherr Schenk von Schmidtburg, to his heir, to whom the largest part of the Koppenstein property fell. Jakob Adolf von Koppenstein returned the family's Sponheim fiefs to the County of Sponheim in 1759. They were lent to his cousin Franz Karl von Hacke (son of Baron Ludwig Anton von Hacke ). Today the ruins and castle district, including Gemünden Castle, belong to the descendants of the Schmidtburger, the barons of Salis .' Here is more detail in a wikipedia about the Kopperstein family.
MyHeritage has a collection of the Koppenstein family tree here.
This castle is south of Kirchberg in Henau. In the Wikipedia the history of Henau, Germany states:
"In 1316, Henau had its first documentary mention in a document from Count Simon II of Sponheim.[2] The Koppenstein Castle ruin, found within the municipality's limits, held town rights beginning in 1330, but had fallen into disrepair by the 16th century. Beginning in 1794, Henau lay under French rule. In 1815 it was assigned to the Kingdom of Prussia at the Congress of Vienna. Since 1946, it has been part of the then newly founded state of Rhineland-Palatinate."
also under building
"Koppenstein Castle ruin, northeast of Henau on a wooded mountain ridge – founding in 10th century (?); upper castle with five-sided keep, latter half of the 13th century; bailey, south, east and north sides girded by doubled ringwall, entrance in the south, beneath the keep remnants of the lodgings, rectangular building with corner turrets."