Castel del Monte in Puglia in southeastern Italy is certainly one of the most famous and mysterious structures in the world. The castle dates back to the time of the Hohenstaufen Emperor Frederick II. and was built from 1240 to around 1250, but never completed. The fortifications and interior work have progressed only marginally, but the outer walls still fascinate today with their mighty sobriety.
There has been much speculation about the function of the fortress, and its octagonal floor plan in particular has inspired fantastic and sometimes even esoteric claims.
Interpretations of the castle’s intended use range from a hunting lodge to a building for storing the imperial regalia, which at the time were located at Trifels Castle in Germany. But why, one wonders, did they choose the peculiar shape?
There have been many theories published. One suggests that the octagon is an intermediate symbol between a square (representing the earth) and a circle (representing the sky). Others write that Frederick II may have been inspired either by the Dome of the Rock in Jerusalem, which he had seen during the Sixth Crusade, or by the Palatine Chapel of Aachen Cathedral. The closest to the truth, however, is certainly an interpretation that was popular in the 1930s to 1950s, according to which the castle was called the Stone Crown of Puglia, as which Castel del Monte was supposed to symbolize the power of Frederick II.
In fact, the octagonal shape is simply the ‘Emperor’s shape’, imitating also the – octagonal – shape of the Imperial Crown, which can still be seen today in Vienna in the Museum.
Frederick II, grandson of the famous Barbarossa from the noble family of the Hohenstaufen, was King of Sicily from 1198, Roman-German King from 1212 and Emperor of the Roman-German Empire from 1220 until his death. His years in power were marked by disputes with the Pope and the struggle for his legitimacy as emperor. He had to fight Saracens and Mongols as well as the communes of Italy and the various high chiefs of Germany, but above all he fought with the Pope.
Because of his openness to the Muslim customs of the Saracens of Sicily and his unwillingness to bow to the Pope’s orders, papal propaganda demonized Frederick as a heretic and antichrist, going as far as to excommunicate him. Among his followers, on the other hand, Frederick was considered the “wonder of the world” (stupor mundi) and his return after his death was so fervently expected that several impostors were able to impersonate him. It is in fact Frederick II who was originally expected to return in the Kyffhäuser – the palace of the Hohenstaufen dynasty – and not Barbarossa.
It is in this context that Frederick chose the octagonal shape of his castle.
Already in the Germanic religions the eight was the symbol of the resurrection. It symbolized the eight months between the disappearance and appearance of the Pleiades and thus the disappearance and return of the goddess Nerthus. In the entire Germanic area, moreover, every eighth year was already introduced in early times as a leap year, in order to add a corrective to the 13 Germanic months with their 28 days.
Also for the Christians the eight and the eighth day was connected with the thought of the resurrection. On Saturday, the seventh day, God had rested, and on Sunday, the eighth day, Jesus had risen from the dead. In the Christian number symbolism of the Middle Ages, eight thus became the number of the new birth, of baptism, and a symbol of the New Covenant. The octagonal form of early Christian baptisteries uses this meaning of the eighth day. This idea is also connected with the fact that, according to biblical tradition, eight people survived the Flood. The eight people expressed God’s covenant with mankind (Noah’s covenant), renewed by Jesus’ death on the cross and his resurrection.
For the occidental Christians, eight is thus the number of baptism, of the connection of heaven and earth, of completion, of the infinite, of redemption, of the Messiah, and thus also logically chosen as the imperial number, which was expressed in architecture in the octagonal basic form of numerous imperial buildings. For this reason, the imperial crown was not round, but octagonal.
Whether Emperor Frederick modeled his castle on the shape of the crown is not certain – after all, he owned several crowns and also lost one of them during a sack of his encampment outside Parma – but it can be assumed as certain that he chose the octagonal shape as a reference to his imperial position. The Hohenstaufen did this elsewhere as well. Take, for example, the shape of the tower of the Abbey of Fossanova, which Barbarossa founded, or just the aforementioned Palatine Chapel in Aachen.
Castel del Monte is octagonal because it was the emperor’s castle. And Frederick II wanted people to see that.
Read more about the secrets of Frederick II and the imperial crown in my book ‘The Proof of God’.