Blankenburg Castle ( Harz ) Great Blankenburg Castle ( ) was built on the limestone hill of " Blankenstein " ( ) in the town of Blankenburg in the district of Harz in the German state of Saxony - Anhalt . Nearby is the Little Castle with its baroque garden , tea house and museum , the town wall , the pheasant garden , the castle park and the castle pond . History . Around 1123 Lothair of Süpplingenburg had Blankenburg Castle built on the Blankenstein . Its suzereignty later passed to the House of Welf through Henry the Proud and Henry the Lion . In 1128 Poppo , from the Frankish noble family of Reginbodonen , was given the county as a fief . His sons shared the county : Conrad received Regenstein Castle and Siegfried I , the Blankenburg . Siegfried I ( Henry the Lion ) did not return from a pilgrimage and left two sons , Henry and Siegfried II . In 1181 the castle and town of Blankenburg were besieged , under the direction of Bishop Dietrich of Halberstadt , by imperial armies . Emperor Frederick Barbarossa took over the reins of power . In 1182 Blankenburg was captured and eventually handed over for plundering . The brothers , Henry and Siegfried II went into captivity , but were given the county back again after peace was re - established . The castle was rebuilt and greatly extended . In 1190 Count Henry took over the " agreed " estates of Regenstein and Siegfried II retained the County of Blankenburg , his descendants keeping possession of Blankenburg until 1343 . Thereafter , the Blankenburg and Regenstein Castle went back to the younger Heimburg line of the House of Regenstein . In 1386 , according to legend , the Blankenburg was supposed to have been secretly looted in the night by Dietrich of Wernigerode , while Count Busso was absent . There is a carved head in the castle wall that recalls this raid . Around 1500 Count Ulrich XI , despite serious debts , had the east wing knocked down and a palace - like building constructed . In 1539 Count Ulrich V broke away from the Roman Catholic Church . On 19 November 1546 a fire broke out at night before the new building had been occupied , which destroyed large parts of the old castle . According to legend , the fire was start with dry kindling by the castle firelighter under the stairs of the old castle , after baptists had paid him with gold . The sleeping residents noticed the fire too late . The maids and servants fled onto the rooftops and out of the windows and down the walls , but forgot their masters . The younger children were dropped out of the windows by their nurses wrapped in blankets . Countess Magdalena of Regenstein was trapped by the flames . The countess asked her husband , Count Ulrich to leave her and save his life . The count escaped through the toilet window and hung from it on the outside before being rescued having been badly burnt . In memory of the fire and the dead , Count Ulrich had a plaque made with inscriptions in Latin and German . It portrays the count , the countess , their six sons and four daughters . In 1599 the House of Regenstein died out and the castle went back to the dukes of Brunswick . In 1705 the conversion of the Renaissance castle into a Baroque residence was started by state architect , Hermann Korb , on behalf of Duke Louis Rudolf of Brunswick - Wolfenbüttel . The reconstruction resulted in a simpler and clearer structure of the outer shape and lasted until 1718 . Also created were reception rooms ( the Grey Hall , Reduten Hall and Imperial Hall ) in the interior , and a multi - storey , octagonal royal church . When Elizabeth Christine married the future emperor , Charles VI , during the time of residence of Louis Rudolf , Emperor Joseph I elevated Blankenburg to the status of a principality . Elisabeth Christine ' s mother later became the Empress Maria Theresa . The family of the Duke Ernest Augustus of Brunswick ( 1887 - 1953 ) and his wife Duchess Victoria Louise , Princess of Prussia ( 1892 - 1980 ) , lived in the castle from 1930 until their flight and the expropriation of their property in 1945 . The family was later given the castle as their private property as compensation in the wake of loss of the principality in 1924 . In 1917 the only daughter of the Duke and Duchess , Frederica , who was later Queen of the Hellenes and mother of the Spanish queen , Sophia , was born here . The court of Blankenburg became famous for its brilliant festivals and theatrical performances .