There is no documentary evidence of the foundation of Frankenstein Castle. It is unclear whether the origins of the hilltop castle in a spur location can be linked to the family of the same name, which was dependent on the Counts of Leiningen. Frankenstein Castle was first mentioned in a document when the House of Leiningen was divided in 1237, but it is very likely that the castle was founded around 1200 by Count Friedrich I Emich von Leiningen, who was enfeoffed with the bailiwick in Speyergau by King Philip of Swabia. In the middle of the 14th century, one half of the castle passed to the Archbishopric of Trier, which appointed its own officials there. In the late Middle Ages, Frankenstein often served as a pawn. The counts of Nassau-Saarbrücken and von Sponheim, among others, appear as pawn lords. Assumptions that the castle was destroyed during the campaigns of Count Palatine Frederick I in 1470/71 or even during the Peasants' War in 1525 lack any relevant documentary evidence. The fact that a Nassau-Saarbrück bailiff was appointed in 1531 speaks against the final destruction and abandonment of the castle after the turmoil of the Peasants' War. The fact that the castle chapel was used for religious services in 1703 speaks against its complete destruction during the French Reuinon Wars at the end of the 17th century.
According to current research, it is unclear when Gräfenstein Castle was abandoned. The last known owners of the castle in the 18th century were the Electors of the Palatinate, the Lords of Wallbrunn, the Lords of Sickingen and the Counts of Leiningen. In 1792, Gräfenstein became state property. Today, the complex is one of the properties managed by the State Palace Administration in Rhineland-Palatinate (Castles - Palaces - Antiquities). (Jens Friedhoff)
The oldest surviving structure of Frankenstein Castle is undoubtedly the keep of the upper castle, which was probably built before 1200 and of which only the lower sections have survived. The castle underwent a significant expansion at the turn of the 13th and 14th centuries, when the impressive multi-storey buildings of the lower castle, which are grouped around the upper castle rock, were built. In the course of architectural archaeological investigations in 1988/89, a previously unknown shield wall from the 12th century was discovered on the south-west side of the lower castle. Among the few late medieval buildings from the 15th century are the curtain wall flanked by a horseshoe-shaped round tower in front of the residential buildings of the lower castle and a small bastion-like fortification in the west of the castle, which secured the main gate in addition to the high medieval shield wall. The final decay of the entire complex probably began in the 18th century. In 1883/84 and 1938/39, the Bavarian State Office for the Preservation of Monuments carried out restoration work. In 1971-74, parts of the façade of the lower castle were added by the Rhineland-Palatinate State Palace Administration. Architectural archaeological investigations were carried out in 1988/89 to accompany the restoration measures. (Jens Friedhoff)
Frankenstein Castle is divided into an upper castle with a rectangular keep, situated on the highest point of the mountain spur, and a lower castle to the south, whose residential buildings were additionally secured by a kennel. The rectangular keep with humpback ashlars (side dimensions 8 x 9 metres) was greatly extended in 1975 with additional walls. On the western attack side, the tower is reinforced like a shield wall. To the south, the main tower is adjoined by a shield wall, which has only been documented since 1989. In the 15th century, a small bastion-like structure was added to the attack side to protect the main gate. The building stock of the lower castle, which adjoins the rock of the upper castle to the south, dates primarily to the late 13th and early 14th centuries. The imposing four- and five-storey buildings facing the valley were added to, particularly in their upper sections, in 1974/75. The south-western residential building is adjoined to the north by a second, almost square residential building (hall-storey building), which dates back to the second half of the 13th century up to the height of the original double windows. The basement of the five-storey building is accessed via an entrance on the north side. The storeys were originally separated by beamed ceilings. Inside, the building has remarkable details. In addition to the window seating niches, the imposing chimney, whose bonnet reached up to the floor above, deserves special attention. The chapel wing adjoins the hall storey building on a separate ledge. The bay window of the chancel protrudes over high-quality consoles. Parts of the surviving kennel wall in the south of the lower castle were probably built in the 15th century (Jens Friedhoff)