Frankenstein Castle Frankenstein Castle ( " Burg Frankenstein " ) is a hilltop castle about 5 km south of Darmstadt in Germany . Modern claims of the castle having an influence on the work of Mary Shelley remain controversial . History . Before 1250 , Lord Konrad II . Reiz von Breuberg erected Frankenstein Castle and since named himself " von und zu " Frankenstein . The first document proving the existence of the castle in 1252 is bearing his name . He was the founder of the free imperial lordship Frankenstein , which was subject only to the jurisdiction of the emperor , with possessions in Nieder - Beerbach , Darmstadt , Ockstadt , Wetterau and Hesse . Additionally the Frankensteins held other possession and Sovereignty - rights as Burgraves in Zwingenberg ( Auerbach ( Bensheim ) ) , in Darmstadt , Groß - Gerau , Frankfurt am Main and Bensheim . The hill whereupon the castle stands was probably occupied by another castle since the 11th century , which fell into ruins after Castle Frankenstein was built a couple of yards to the northwest . Claims of an even older predecessor upon the hill are widespread , but historically unlikely . In the year 1292 the Frankensteins opened the castle to the counts of Katzenelnbogen ( County of Katzenelnbogen ) Katzenelnbogen and leagued with them . In 1363 , the castle was split into two parts and owned by two different families of the lords and knights of Frankenstein . At the beginning of the 15th century , the castle was enlarged and modernized . The Frankenstein knights became independent from the Counts of Katzenelnbogen again . Being both strong opponents of the reformation and following territorial conflicts , connected disputes with the Landgraviate of Hesse - Darmstadt , as well as the adherence to the catholic faith and the associated " right of patronage " , the family head Lord Johannes I . decided to sell the lordship to the Landgraves of Hesse - Darmstadt in 1662 , after various lawsuits at the Imperial Chamber Court . The castle was used as refuge and a hospital afterward , falling into ruins in the 18th century . Two towers , which are so distinctive today , are a historically inaccurate restoration of the mid - 19th century . Sometime prior to 1968 , a restaurant was built within the castle . In 1978 , American Airman from the 435th Transportation squadron stationed at Rhein Mein Air Base founded an annual Halloween festival at the castle , which has grown to become one of the biggest Halloween festivals in Europe . In 1977 , the 440th Signal Battalion organized a 13 kilometer running race routed along steep forest trails from Cambrai - Fritsch Kaserne to the castle . The Frankenstein Castle Run was held until 2008 , when American forces left Darmstadt and the base was turned over to the German government . The City of Darmstadt organized a final race in October 2008 . Johann Conrad Dippel . In 1673 , the alchemist Johann Conrad Dippel was born at the castle . He was very famous during his lifetime . There have been claims of Dippel influencing Mary Shelley to write her Frankenstein novel , though there is no mention of the castle in Mary ' s journals from the time . It is known that in 1814 , prior to writing the famous novel , Mary took a journey on the river Rhine . She spent a few hours in the town of Gernsheim , which is located about ten miles away from the castle . Though much of what has been said about Dippel to support this theory has turned out to be false , several nonfiction books on the life of Mary Shelley claim Dippel as a possible influence .