Aggersborg is the largest of Denmark's former Viking ring castles, and one of the largest archeological sites in Denmark. It consisted of a circular rampart surrounded by a ditch. Four main roads arranged in a cross connected the castle centre with the outer ring. The roads were tunnelled under the outer rampart, leaving the circular structure intact.
The ring castle had an inner diameter of 240 metres. The ditch was located eight metres outside of the rampart, and was approximately 1.3 metres deep. The wall is believed to have been four metres tall. The rampart was constructed of soil and turf, reinforced and clad with oak wood. The rampart formed the basis for a wooden parapet. Smaller streets were located within the four main sections of the fortress.
The modern Aggersborg is a reconstruction created in the 1990s. It is lower than the original fortress.
Dating the structure has proven difficult, since the archaeological site has also been the site of an Iron Age village. The ring castle is believed to have been constructed around 980 during the reign of king Harold Bluetooth and / or Sweyn Forkbeard. Five of the six ring castles in historical Denmark have been dated to this era. The structure was completed within one or two years, and only used for a short period of time; between five and twenty years.
Archaeologists have estimated that the ring castle could hold a 5,000-man garrison, located in 48 longhouses. Twelve longhouses were located in each quadrant, all located on a north-south or west-east axis. No remains of the actual houses exist, but proof of the location of the walls has been found. The individual houses are believed to have been similar to the form seen on the Camnin chest, a house-shaped reliquary, as well as on house-shaped tombstones in England.
The houses had curved roofs and curved sides, similar to the form of a ship; 32.5 metres long and 8.5 metres across. They were divided in a long inner hall, around 19 metres long, with smaller rooms at the end. It is estimated that construction of a single Aggersborg house required 66 large oak trees. The entire structure, housing included, is estimated to have used 5,000 large oaks.
A large number of archaeological finds have been discovered on the site, including many imported luxury items. Examples include beads of mountain crystal and pieces of glass jars. A damaged golden ring has been discovered on the site as well; a replica is displayed in the Aggersborg museum.
No conclusive data yet exists whether Aggersborg was a stronghold controlling trade routes or whether its primary function was as a barracks / training grounds in connection with Sweyn Forkbeard's Viking raids on England.
References:The ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.