Burg Frankenstein, Medieval castle in Bad Salzungen, Germany

Burg Frankenstein is a ruined spur castle on a ridge at 280 m above sea level, about 2 km east of Bad Salzungen's centre near the Kloster district. Only earthworks survive: a roughly rectangular core of about 80–100 by 40–60 m, two crescent-shaped ramparts and ditches on the east side, and a deep neck ditch on the north. The steep southern slope drops 30–50 m to the Werra valley.

Burg Frankenstein was the ancestral seat of the Frankenstein lords, a line descended from the Counts of Henneberg. The castle is first mentioned indirectly in 1137, when Ludwig, son of the lineage's founder Poppo von Frankenstein, named himself after it; by 1153 the lords are documented as ministeriales of Hersfeld Abbey. Abbot Bertho II of Fulda besieged and partly destroyed it in 1265, and King Adolf did the same in 1295. It last mattered in 1335, and its complete destruction in the Peasants' War is likely.

The name Frankenstein comes from popular tradition: the site was said to be one of the first stone castles in the Werra valley, built by a district count of the East Frankish kings. The castle was the ancestral seat of the lords of Frankenstein, a line descended from the counts of Henneberg.

The path to the ruins leads through woodland and can be steep in places, so sturdy footwear is a good idea. If you want a guided tour in German, it is worth arranging this in advance before your visit.

About 100 metres east of the medieval castle, on the summit of the same hill, the Frankensteingemeinde association built a mock ruin with a viewing tower around 1890. Stones for it were dug from the medieval site, destroying cellars and wall remains still known around 1830.