Fyrkat might be the oldest of Denmark's former Viking ring castles. It is built on a narrow piece of land with a river on one side and swampy area on the others. It could have controlled the traffic on the main land route between Alborg and Aarhus. Like the other forts at Aggersborg or Trelleborg near Slagelse it is designed as exact circle with four gates opposite to each other and connected by two wooden roads that cross in a right angle in the exact middle of the fort. A circle road gave access to the wall. In each of the four quarters stood four longhouses of the same design arranged in a square with a smaller house in the middle.
The inner diameter of the ramparts was 120 meters and the width at the base 12–13 meters. They were constructed of three rows of vertical wooden poles. Each pole connected to the next ring by beams. The innermost row was the lowest and the gaps filled horizontal with planks forming a wall to the inside of the fort. The middle row was as high as the earthwork and carried the inner side of the walkway. The earth fill sloped to the inside so the ramparts could be easily accessed from every point of the circle road. The outer row of poles was strengthened on the inside and outside with slanted beams at the base. They probably were higher than the middle row and supported a parapet. The gaps between the posts were again filled horizontally with planks but on the outside there was also a wall of vertical trunks slightly leaning to the wall. The space in between the post rows was stacked with some 10000 cubic meters of turf. On the wall there was a walkway made of planks. The outer wall is presumed to have stood some four meters high. The northeast quarter was protected by a ditch with pointed bottom about 7 to 8 meters wide and under 2 meters deep. The ditch on the west and southwest side was never finished. The other sides were protected by a river and rather swampy area. A structure in front of the west gate my have been a gatehouse of some sort.
The roads inside the fort were founded on three to five rows of short poles rammed into the ground and supporting strong beams running lengthwise along the rows. These were then topped by strong planks spanning the width of the road. The circle road along the inside of the ramparts rested on two rows of beams.
The 16 identical longhouses were arranged in a square with the corners almost touching. They were 28.5 meters long (96 roman feet of 29.6 cm), 5 meters wide at the ends and 7.5 meters in the middle, the long walls slightly curved to the outside. The walls consisted of double rows of posts with planks wedged horizontal between them to make a wall. Along the outside ran a row of posts slanted to the wall either to support it at the top like buttresses or maybe even in some sort of cruck like construction being the rafters of the roof. On how the roof was built exactly the opinions differ. It might have been coated with reeds or maybe wood shingles or even a construction of planks similar to the ships. Inside the houses, each end was walled off to make a small room, maybe a pantry or storeroom. The two small rooms had doors to the outside on the short end and could be accessed from the large middle room in the inside. Near the ends of the 18 meters long great middle room each long wall had a door set diagonal to the door on the other side that led into a small porch with a door to the outside. On the inside the great room had a large hearth in the middle and a raised wide bank alongside the outer walls for sleeping. Of the longhouses in Fyrkat at least two contained smithies and gold was worked with in two others. About a quarter of the excavated houses seem to have been warehouses of some sort.
The site was excavated between 1950 and 1958 by the Architect and Museum Inspector C.G.Schultz. The ramparts, that had almost been ploughed level through the ages were piled up again and the postholes of the roads and buildings were filled with concrete.
The museum at Hobro houses most of the things found at Fyrkat. Most was found in the graveyard to the northwest of the fort that had a wooden planked road lead to it. The most precious find was a piece of gold jewelry with nice birds head. In the about 30 graves of men, women and children some were buried in wagon crates such as found in Osebergothers in coffins. The poor were randomly mixed with the rich.
The very similar castle Trelleborg near Slagelse has been dated precisely to the spring of 981 by tree ring dating, Fyrkat might be a year or two older, Aggersborg could be slightly younger. Not enough was found at Nonnebakken to make an exact enough dating possible. Yet the forts are so extremely similar that it seems most probable that they were conceived by a single mind. Fyrkat seems to have been inhabited only for a rather short period of time, maybe not much more than a decade, maybe even less. By the year 1000 the fort seems to have been deserted and shortly after had simply burned to the ground without any evidence of fighting.
Besides the ramparts that rather represent just the volume of the original than the construction, a longhouse was reconstructed in 1985 just outside of the fort. It claims to be somewhat more accurate than the first one reconstructed in 1948 at Trelleborg near Slagelse.
In recent years a 'Viking Center' has been built about one kilometre from the fort. It resembles a large farm with a big longhouse finished in 1993, a smithy, a barn and some smaller buildings along with a visitors center. Its main aim seems to be educational and thus presenting a complete Viking age environment here on the model of a supplier for the fort. None such farm was ever found near Fyrkat though, the buildings being reconstructed after examples excavated in Vorbasse, a small town in southern Jutland.References:
The Porta Nigra (Latin for black gate) is the largest Roman city gate north of the Alps. It is designated as part of the Roman Monuments, Cathedral of St. Peter and Church of Our Lady in Trier UNESCO World Heritage Site. The name Porta Nigra originated in the Middle Ages due to the darkened colour of its stone; the original Roman name has not been preserved. Locals commonly refer to the Porta Nigra simply as Porta.
The Porta Nigra was built in grey sandstone between 186 and 200 AD. The original gate consisted of two four-storied towers, projecting as near semicircles on the outer side. A narrow courtyard separated the two gate openings on either side. For unknown reasons, however, the construction of the gate remained unfinished. For example, the stones at the northern (outer) side of the gate were never abraded, and the protruding stones would have made it impossible to install movable gates. Nonetheless, the gate was used for several centuries until the end of the Roman era in Trier.
In Roman times, the Porta Nigra was part of a system of four city gates, one of which stood at each side of the roughly rectangular Roman city. The Porta Nigra guarded the northern entry to the Roman city, while the Porta Alba (White Gate) was built in the east, the Porta Media (Middle Gate) in the south, and the Porta Inclyta (Famous Gate) in the west, next to the Roman bridge across the Moselle. The gates stood at the ends of the two main streets of the Roman Trier, one of which led north-south and the other east-west. Of these gates, only the Porta Nigra still exists today.
In the early Middle Ages the Roman city gates were no longer used for their original function and their stones were taken and reused for other buildings. Also iron and lead braces were broken out of the walls of the Porta Nigra for reuse. Traces of this destruction are still clearly visible on the north side of the gate.
After 1028, the Greek monk Simeon lived as a hermit in the ruins of the Porta Nigra. After his death (1035) and sanctification, the Simeonstift monastery was built next to the Porta Nigra to honor him. Saving it from further destruction, the Porta Nigra was transformed into a church: The inner court of the gate was roofed and intermediate ceilings were inserted. The two middle storeys of the former gate were converted into church naves: the upper storey being for the monks and the lower storey for the general public. The ground floor with the large gates was sealed, and a large outside staircase was constructed alongside the south side (the town side) of the gate, up to the lower storey of the church. A small staircase led further up to the upper storey. The church rooms were accessible through former windows of the western tower of the Porta Nigra that were enlarged to become entrance doors (still visible today). The top floor of the western tower was used as church tower, the eastern tower was leveled, and an apse added at its east side. An additional gate - the much smaller Simeon Gate - was built adjacent to the East side of the Porta Nigra and served as a city gate in medieval times.
In 1802 Napoleon Bonaparte dissolved the church in the Porta Nigra and the monastery beside it, along with the vast majority of Trier"s numerous churches and monasteries. On his visit to Trier in 1804, Napoleon ordered that the Porta Nigra be converted back to its Roman form. Only the apse was kept; but the eastern tower was not rebuilt to its original height. Local legend has it that Napoleon originally wanted to completely tear down the church, but locals convinced him that the church had actually been a Gaulish festival hall before being turned into a church. Another version of the story is that they told him about its Roman origins, persuading him to convert the gate back to its original form.
In 1986 the Porta Nigra was designated a World Heritage Site, along with other Roman monuments in Trier and its surroundings. The modern appearance of the Porta Nigra goes back almost unchanged to the reconstruction ordered by Napoleon. At the south side of the Porta Nigra, remains of Roman columns line the last 100 m of the street leading to the gate. Positioned where they had stood in Roman times, they give a slight impression of the aspect of the original Roman street that was lined with colonnades. The Porta Nigra, including the upper floors, is open to visitors.