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VIKING MONUMENTS AND SITES / The Trelleborg fortresses, Denmark

Date of Submission: 07/02/2011
Criteria: (iii)
Category: Cultural
Submitted by:
Heritage Agency of Denmark
State, Province or Region:
Vesthimmerlands Municipality, Mariagerfjord Municipality and Slagelse Municipality
Ref.: 5582
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The sole responsibility for the content of each Tentative List lies with the State Party concerned. The publication of the Tentative Lists does not imply the expression of any opinion whatsoever of the World Heritage Committee or of the World Heritage Centre or of the Secretariat of UNESCO concerning the legal status of any country, territory, city or area or of its boundaries.

Property names are listed in the language in which they have been submitted by the State Party


Part of transnational serial nomination

Aggersborg N56 59 43, E9 15 17;

Fyrkat N56 37 23, E9 46 13;

Trelleborg N55 23 39, E11 15 55

The Viking serial nomination comprises land-, sea- and townscapes stretching from the North Atlantic to the Baltic Sea. Among the thousands of Viking sites from the eighth to the twelfth centuries AD, these nine nominated properties from six nations are outstanding examples representing the wide diversity of this early maritime culture.

In the Viking Age the Norse peoples - the Vikings - developed a maritime culture which had an enormous impact on Northern Europe and beyond. Within Scandinavia the Viking Period witnessed the transformation from tribal to state societies and a change of religions. The three Christian kingdoms that developed from this transformation, and out of which the present Nordic States evolved, were by the end of the Viking Age an integral part of Europe. Thus, in modern times, Viking culture has contributed significantly to the creation of cultural coherence, symbolic values and cultural identity in the Nordic region, and it continues to hold immense public appeal world-wide. This culture and its heritage developed in close interaction within a unique natural environment. It is composed of distinctive urban landscapes and monuments. The culture also produced one of the world's great literatures: the Sagas, Eddic poetry and runic inscriptions.

Harnessing the technology of the ship, Vikings used the sea for expansion, exploration, longdistance trade and overseas settlement. The travels of the Vikings brought them across the Baltic Sea and down the Russian rivers as far as the Black and Caspian Seas to Byzantium and the Caliphate of Baghdad, as well as west out into the Atlantic. They were the first to settle in Iceland and the first Europeans to reach Greenland and North America about 1000 AD. In so doing, the Vikings were the first people to succeed in opening routes across the northern hemisphere from North America to Asia, thus connecting different cultural regions of the earth. Adapted to very diverse types of natural environments, success was on the one hand in the use, and at times ecological misuse, of regional resources, and, on the other hand, in the development of social and political systems. This combination formed the basis for a rich cultural region. Internally, Scandinavia witnessed an economic, religious and social transformation aided by a boom in internal and cross-cultural communication during the Viking period. New institutions were developed, smaller regions were merged into larger units and the Scandinavians took part in European development on a larger scale. Scandinavia at the time of King Knut, in the early 11th century, was vastly different from the Scandinavia that was visited by the missionary Ansgar in the early 9th century.

The component parts cover a wide temporal and spatial range. They are of exceptional quality and diversity. They include trading towns, harbours, defensive structures, production sites, burial monuments, and assembly sites. Viewed as a whole these sites bear witness to the extent of Viking social and cultural development.


The Trelleborg fortresses include Trelleborg near Slagelse, Fyrkat near Hobro, Aggersborg near Løgstør and Nonnebakken in Odense, of which only the former three have been preserved for posterity. The Trelleborg fortresses are characterised by having a circular rampart with a moat and four roofed gates. The fortresses have a severely geometrical street system, the inner area being divided into squares, each with four longhouses arranged in a quadrangle. The architecture of all four fortresses is uniform and strictly symmetrical, as clearly illustrated by the circular shape of the fortifications and the location of the gates at the four points of the compass - apparently without regard to the terrain.

Dendrochronological tests and C14 tests have shown that the Trelleborg fortresses were built around 980. But the fortresses probably did not last very long, perhaps only 10 to 20 years. For example, Fyrkat was destroyed by fire and was not rebuilt. As the Trelleborg fortresses were all built around 980, they have traditionally been linked to Harald Bluetooth's efforts to unify Denmark and Norway and make the Danes Christian in accordance with his runic stone proclamation. Another interpretation links the fortresses to the conquest of England and therefore to Harald Bluetooth's son, Sweyn Forkbeard. Whatever the case, the fortresses must be viewed as a monumental and military manifestation of the central power of the late Viking era.

Individual elements of the property and their mutual relationship, including to the landscape:

The fortresses are all located in landscapes typical of their respective regions, in river valleys and relatively close to the coast. At both Trelleborg and Fyrkat, extensive nature restoration projects have been conducted over the last decade in order to recreate the natural conditions prevailing at the time of the fortresses. The landscapes surrounding the fortresses thus clearly demonstrate the strategic location of the fortresses and the military reasons for building them at what must be described as Viking era junctions.

Today, the visible elements are the fortifications, which include the ring fortress and the related defences and, at Trelleborg, a perimeter fort and moat. The original ramparts consisted of a complex oak-wood structure with an inner skeleton and outer lathing. As any buildings on the parapet and above the gates can only be reconstructed on a hypothetical basis, the fortresses are only visible in the landscape today in the form of marked embankments without woodwork or moats. Furthermore, at Fyrkat and Trelleborg the houses are marked on the surface of the ground. In addition, reconstructions of the longhouses traceable inside the fortresses have been built outside Fyrkat and Trelleborg, respectively.

Justification of Outstanding Universal Value

The selection of sites bears an exceptional testimony to a unique cultural tradition in which the ship became the essential feature. Due to the natural environment of lakes, rivers and sea the use of waterways and the development of navigational skills had a long tradition. In the Viking Age ship technology was taken to a new level. Vikings were the first to settle in Iceland and the first Europeans to reach Greenland and North America about 1000 AD. In so doing, the Vikings were the first people to succeed in opening routes across the North Atlantic to North America and eastward to the Russian Plain and Byzantium, connecting continents and cultural regions. Internally, Scandinavia witnessed an economic, religious and social transformation aided by a boom in internal and cross-cultural communication during the Viking period. The component parts represent key attributes of Viking culture while the ship is the common feature throughout. In modern times, Viking culture has contributed significantly to the creation of cultural coherence, symbolic values and cultural identity in the Nordic region, and it continues to hold immense public appeal world-wide. The component parts demonstrate clearly the key features; expansion, cultural communication and a strong narrative tradition past and present.

The ring fortresses, Trelleborg, Aggersborg and Fyrkat, represent the most prominent archaeological evidence of the monumental defences of the Viking era in present-day Denmark. No contemporary counterparts exist in either the Nordic countries or Europe. The fortresses are a unique architectural testimony to the state formation in 10th century and reflect the outstanding technology and engineering of Viking Culture, which also express itself in the timber palisade of Jelling. Furthermore, the fortresses should be viewed in relation to the expansion of Dannevirke. These contemporary monumental buildings testify Harald Bluetoooth's power, capacity and ability in organizing.

Statements of authenticity and/or integrity

Archaeological investigations of large parts of the fortresses have been conducted and presented in several scientific publications of a high standard. The archaeological investigations documented that the fortresses were largely unaffected by later use, apart from cultivation. Following the archaeological investigations, the collapsed ramparts at Trelleborg and Fyrkat were marked in the terrain, and the moats were cleared. At Aggersborg, where the original embankments had to a wide extent been levelled by ploughing, the rampart and the moat were re-established. All these works and the marking of other structures inside or near the fortresses were conducted on the basis of the complete and detailed documentation provided as a result of the excavations.

Comparison with other similar properties


The transnational project unites properties already appointed as Viking Age World Heritage with the newly nominated sites of Danevirke and Hedeby as well as GrobiĦa, the Danish fortresses, the Vestfold burial mounds and Hyllestad quernstone quarry. They all rank among the most important historical places in the Viking Age and have moreover, as archaeological sites, contributed essential insights into Scandinavian culture of this period. In this period the Nordic region developed from being a peripheral zone of Europe to being an integrated component of the Christian West. Of exceptional value is the good condition of preservation displayed by the project's combined monuments, ideally complemented by Old Iceland's rich supply of written records and by other outstanding archaeological finds such as the ships from Gokstad, Oseberg and Roskilde. Corresponding nominations for the period between the 8th and the 12th century AD have to date not been represented on the World Heritage List.

The Trelleborg Fortresses:

No similar fortresses from the Viking era exist. Therefore, it is hardly possible to tell what inspired the construction of the Trelleborg fortresses.

The Trelleborg fortresses cannot be viewed in isolation; they must be considered in a historical context that includes the Jelling burial mounds and the Kovirke defences at Dannevirke. Jelling should be considered because the construction of the Trelleborg fortresses is traditionally ascribed to Harald Bluetooth, who buried his parents in Jelling and erected a runic stone for them describing his own achievement of consolidating the realm. It is believed that the Trelleborg fortresses were of great significance in this respect.

Based on the straight line of Kovirke and its C14 dating to the time around 980, this defence embankment located a few kilometres south of Dannevirke is considered to have been constructed at the same time and possibly by the same builder as the Trelleborg fortresses.