Castel del Monte , Apulia Castel del Monte ( , Bari dialect : " Castídde d ' u Monte " ) is a 13th - century citadel and castle situated in Andria in the Apulia region of southeast Italy . It stands on a promontory , where it was constructed during the 1240s by the Emperor Frederick II , who had inherited the lands from his mother Constance of Sicily . In the 18th century , the castle ' s interior marbles and remaining furnishings were removed . It has neither a moat nor a drawbridge and some considered it never to have been intended as a defensive fortress ; however , archaeological work has suggested that it originally had a curtain wall . Described by the Enciclopedia Italiana as " the most fascinating castle built by Frederick II " , the site is protected as a World Heritage Site . Location . Castel del Monte is situated on a small hill close to the monastery of Santa Maria del Monte , at an altitude of 540 m . When the castle was built , the region was famously fertile with a plentiful supply of water and lush vegetation . It lies in the " comune " of Andria , occupying the site of an earlier fortress of which no structural remains exist . The castle ' s construction is mentioned in only one contemporary source , a document dating to 1240 , in which the Holy Roman Emperor Frederick II ordered the governor of Capitanata to finish some works in it . It was never finished and there is no proof that the emperor used it as a hunting lodge as commonly stated . It was later turned into a prison , used as a refuge during a plague , and finally fell into disrepair . It originally had marble walls and columns , but all were stripped by vandals or re - used in constructions nearby . Description . Because of its relatively small size , it was once considered to be no more than a " hunting lodge " , but scholars now believe it originally had a curtain wall and did serve as a citadel . Frederick was responsible for the construction of many castles in Apulia , but Castel del Monte ' s geometric design was unique . The fortress is an octagonal prism with an octagonal tower at each corner . The towers were originally some 5 m higher than now , and they should perhaps include a third floor Both floors have eight rooms and an eight - sided courtyard occupies the castle ' s centre . Each of the main rooms have vaulted ceilings . Three of the corner towers contain staircases . The castle has two entrances , an unobtrusive service entrance and an ornate main entrance . Frederick ' s main entrance featured elements from classical design , and may have been influenced by Frederick ' s interest in Greco - Roman architecture . The octagonal plan is unusual in castle design . Historians have debated the purpose of the building and it has been suggested that it was intended as a hunting lodge . Another theory is that the octagon is an intermediate symbol between a square ( representing the earth ) and a circle ( representing the sky ) . Frederick II may have been inspired to build to this shape by either the Dome of the Rock in Jerusalem , which he had seen during the Sixth Crusade , or by the Palace Chapel of Aachen Cathedral . Occasionally used in this way under Manfred of Sicily , the castle become a state prison under the latter ' s victor , Charles I of Anjou : here Manfred ' s sons Henry , Azzo and Enzo were kept as prisoner after 1266 , as well as other Hohenstaufen supporters The main wall is 25 m high and the eight bastions each 26 m . The sides of the main octagon are 16 . 5 m long and those of the octagonal towers each 3 . 1 m . The castle has a diameter of 56 m . Its main entrance faces east . Modern era . In the 18th century , the castle ' s marbles and other ornamentation were looted . Members of the House of Bourbon took the marble columns and window frames and reused them at their palace in Caserta . What remains now includes fragments of a knight and a re - used Roman relief , while in the Provincial Gallery of Bari there are a head fragment and a cloaked , headless bust , sometimes interpreted as Frederick II . After having been abandoned for a considerable length of time , the castle was purchased in 1876 for the sum of 25 , 000 lire by the Italian State , which began the process of restoration in 1928 . Central to the plot of Umberto Eco ' s novel " The Name of the Rose " is an old fortress known as the ' Aedificium ' . This was almost certainly inspired by Castel del Monte . In 1996 Castel del Monte was named a World Heritage Site by UNESCO , which described it as " a unique masterpiece of medieval military architecture " . Castel del Monte is depicted on the reverse of the Italian - issue 1 Euro cent coin . Soil around the castle was discovered to contain a bright red compound produced by a strain of the bacterium Streptomyces peucetius . Scientists named the drug Daunorubicin and further development identified a related compound Doxorubicin that finds use as a chemotherapeutic agent used to treat cancer . Castel del Monte DOC . Around the castle , Andria is the Italian DOC wine region of Castel del Monte that produces red , white and " rose " wines . Most of the wines are blends but varietal wines can be produced as long as at least 90 % of the wine is composed of the same grape . The reds are usually a blend of 65 - 100 % Uva di Troia , up to 35 % of Sangiovese , Montepulciano , Pinot noir and Aglianico . The " roses " include 65 - 100 % Uva di Troia and / or Bombino nero with the other red grape varieties filling out the rest . The whites are composed mainly of Pampanuto ( 65 - 100 % ) with other local white grape varieties filling out the rest . Red and " rose " grapes are limited to a harvest yield of 14 tonnes / ha and must make a wine with a minimum of 12 % alcohol level ( 11 % in the case of " rose " ) . White wine grapes are limited to a harvest yield of 15 tonnes / ha and must make a wine with a minimum alcohol of 11 % . If the wine is to be labeled a " Riserva " , the wine must be aged at least 2 years with one of those years in oak / wood and must have a minimum alcohol level of 12 . 5 % .