Nonnebakken (literally, "Nun Hill") is the site of one of Denmark's six former Viking ring castles, built during the reign of Sweyn Forkbeard, who had forced his father Harold Bluetooth to leave the country and seek refuge by the Jomsvikingson Wollin (modern Poland) around 975. The fort enabled its occupier command of the Odense River passing next to the hill.
The name refers to the Benedictine Nunnery located on the site at earlier times. To the end of the 12th century the Nuns left the site to build a new Church in Dalum to the southeast, now a suburb of Odense.
The earthworks can still be recognized in the panorama of Odense in the 'Civitates Orbis Terrarum' from Georg Braun and Frans Hogenberg. The engraving is in volume 5, that was finished in 1598 (although first published in 1612-18 in Cologne), on plate 30, that was made in 1593 from information contributed by Heinrich Rantzau or from sketches he gave in order. It also appears on the panorama of Odense published by Braunius in 1593.
The archaeological remains of the fort took heavy damage when a building for the Odd Fellow lodge was constructed on the site during the late nineteenth century. The site was excavated by the Fyns Stiftsmuseum. The castle had a diameter of 120 m and dates to 980-1000, similar to the other Viking ring castles.
Although finds have been reported from 1775 and 1889 the extent of the whole structure was first determined in 1953. The next major gain in Information was when in 1988 trenches where dug for laying cables. A ditch with pointed bottom was observed during the excavations. It was at least four meters wide and two meters deep with a berm of maximal 10 to 12 meters. The later filling could be dated to the time of the abbey. The profile of a ditch with pointed bottom eight meters wide and some four meters deep was excavated in the northeast and the northwest. During excavations prior to larger diggings for heating pipes in 1995/97/98 a ditch eleven meters wide and three meters deep was observed. A spade made of oak was found that was dated with dendrochronology to the functioning time of the structure. Excavations in 2002 revealed parts of the abbey.References:
Hochosterwitz Castle is considered to be one of Austria's most impressive medieval castles. The rock castle is one of the state's landmarks and a major tourist attraction.
The site was first mentioned in an 860 deed issued by King Louis the German of East Francia, donating several of his properties in the former Principality of Carantania to the Archdiocese of Salzburg. In the 11th century Archbishop Gebhard of Salzburg ceded the castle to the Dukes of Carinthia from the noble House of Sponheim in return for their support during the Investiture Controversy. The Sponheim dukes bestowed the fiefdom upon the family of Osterwitz, who held the hereditary office of the cup-bearer in 1209.
In the 15th century, the last Carinthian cup-bearer, Georg of Osterwitz was captured in a Turkish invasion and died in 1476 in prison without leaving descendants. So after four centuries, on 30 May 1478, the possession of the castle reverted to Emperor Frederick III of Habsburg.
Over the next 30 years, the castle was badly damaged by numerous Turkish campaigns. On 5 October 1509, Emperor Maximilian I handed the castle as a pledge to Matthäus Lang von Wellenburg, then Bishop of Gurk. Bishop Lang undertook a substantial renovation project for the damaged castle.
About 1541, German king Ferdinand I of Habsburg bestowed Hochosterwitz upon the Carinthian governor Christof Khevenhüller. In 1571, Baron George Khevenhüller acquired the citadel by purchase. He fortified to deal with the threat of Turkish invasions of the region, building an armory and 14 gates between 1570 and 1586. Such massive fortification is considered unique in citadel construction.
Since the 16th century, no major changes have been made to Hochosterwitz. It has also remained in the possession of the Khevenhüller family as requested by the original builder, George Khevenhüller. A marble plaque dating from 1576 in the castle yard documents this request.
A specific feature is the access way to the castle passing through a total of 14 gates, which are particularly prominent owing to the castle's situation in the landscape. Tourists are allowed to walk the 620-metre long pathway through the gates up to the castle; each gate has a diagram of the defense mechanism used to seal that particular gate. The castle rooms hold a collection of prehistoric artifacts, paintings, weapons, and armor, including one set of armor 2.4 metres tall, once worn by Burghauptmann Schenk.