Tissø is the 4th largest

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

lake in

Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...

, at 12.3 km². It is located on the western part of

Zealand Zealand ( ) is the largest and most populous islands of Denmark, island in Denmark proper (thus excluding Greenland and Disko Island, which are larger in size) at 7,031 km2 (2715 sq. mi.). Zealand had a population of 2,319,705 on 1 Januar ...

, in the municipality of

Kalundborg Kalundborg () is a Danish city with a population of 16,659 (1 January 2025),Kalundborg Kalundborg () is a Danish city with a population of 16,659 (1 January 2025),Kalundborg Eco-industrial Park.

Etymology

Tissø means 'The God's Lake', but the etymology and meaning is not obvious. Basically the name can be broken into ''Tis-sø'', where ''sø'' means 'lake' in a literal and simple translation from Danish to English. ''Tis'' is the more interesting part and refers to the old god Tir, who have given name to many places in Denmark such as Tisvilde, Tirslund or Thisted, for example, and Tissø was originally known as 'Tir's Lake'. However, the word ''Ti'' is also an

Old Danish The Danish language developed during the Middle Ages out of Old East Norse, the common predecessor of Danish and Swedish. It was a late form of common Old Norse. The Danish philologist Johannes Brøndum-Nielsen divided the history of Danish in ...

word meaning 'God', without being specific. For unknown reasons, it appears that at some point during the

Iron Age The Iron Age () is the final epoch of the three historical Metal Ages, after the Chalcolithic and Bronze Age. It has also been considered as the final age of the three-age division starting with prehistory (before recorded history) and progre ...

, the new god

Tor Tor, TOR or ToR may refer to: Places * Toronto, Canada ** Toronto Raptors * Tor, Pallars, a village in Spain * Tor, former name of Sloviansk, Ukraine, a city * Mount Tor, Tasmania, Australia, an extinct volcano * Tor Bay, Devon, England * Tor ...

took over Tir's role as a god of war. In relation to Lake Tissø, this religious change would imply that the name means 'The God's Lake', relying on the meaning of the word ''ti'', without being specific about which god, or gods for that matter.Tissø
Department of Scandinavian Research, University of Copenhagen In recent years, a slightly different understanding of the origins of the name Tissø have emerged. It is possible that the name originally was ''Tis-ø'' and that the extra ''s'' was added later on, when name-recording was needed. The pronunciation of ''Tissø'' and ''Tis-ø'' is almost the same, but the later translates as 'Tir's Island', possibly referring to the area around Fugledegård on the western shore of the lake. Fugledegård was once a settlement and a magnates residence in the

Viking Age The Viking Age (about ) was the period during the Middle Ages when Norsemen known as Vikings undertook large-scale raiding, colonising, conquest, and trading throughout Europe and reached North America. The Viking Age applies not only to their ...

, situated on a relatively high lying area, that used to be an

islet An islet ( ) is generally a small island. Definitions vary, and are not precise, but some suggest that an islet is a very small, often unnamed, island with little or no vegetation to support human habitation. It may be made of rock, sand and/ ...

. Remains of a

cult Cults are social groups which have unusual, and often extreme, religious, spiritual, or philosophical beliefs and rituals. Extreme devotion to a particular person, object, or goal is another characteristic often ascribed to cults. The term ...

-house have been excavated and there are numerous remains of animal sacrifices and religious practises at Fugledegård. There is no doubt that the area was an important religious site in former ages and it is possible that it gave name to the entire lake. There are many myths and legends about the origin of lake Tissø.

History

The lake of Tissø was created after the ice receded, at the end of the last ice age. Parts of the ice cover were left behind and landlocked in valleys of the virgin lands. Such ice pockets are known as

dead ice Dead ice is the ice in a part of a glacier or ice sheet that is no longer moving. As the ice melts, it leaves behind a hummocky terrain known as dead-ice moraine. Dead-ice moraine is produced by the accumulation of sediments carried by glaciers t ...

and as the climate steadily warmed up, they melted and turned into freshwater lakes also known as kettle holes. Tissø have always had a great importance for the people living here. In the earliest of times, humans hunted around the lake in the summer months and there are numerous traces of their activities in the area and the wetlands now surrounding the lake. Maglemosen southwest of the lake and Åmosen to the east, are of special mention here, since they have revealed defining archaeological finds of the so-called

Maglemosian culture Maglemosian ( 9000 – 6000 BC) is the name given to a culture of the early Mesolithic period in Northern Europe. In Scandinavia, the culture was succeeded by the Kongemose culture. Environment and location The name originates fr ...

and Kongemose culture, in the years 1900 and 1952 respectively. Later on, when the climate warmed up and people begun to build permanent settlements, the lake also became important as a place for the deposition of votive offerings. There have been many finds from the

and

and the cult practices continued on after the Christianization of Denmark even.

Kalmargården

There are several excavations of Iron Age settlements around Tissø and in 1976 a large golden ornamental ring manufactured in the 10th century, was unearthed during a regular field-plowing. The Tissø Ring is a neck-ring with a diameter of 30 cm and at 1.83 kg (originally 2 kg), it is one of the largest gold finds in Denmark. Picture of the Tissø Ring. This led to professional investigations and remains of a Viking estate was discovered at the site now known as 'Kalmargården', near Fugledegård on the western lakebrink. In 1995-2003 large scale excavations revealed, that the total settlement covered c. 500,000 m² (50 ha), centered around a 12 x 48 m hall and with several buildings and structures believed to have ritualistic purposes. In 2012 remains of another large hall measuring 8 x 35 m was discovered. The magnates residence of Kalmargården, greatly resemble the residences excavated at 'Old

Lejre Lejre is a railway town in the northwestern part of the island of Zealand (Denmark), Zealand in eastern Denmark. It has a population of 3,165 (1 January 2024) inhabitants.

' in central Zealand and at

Järrestad A hundred is a geographic division formerly used in northern Germanic countries and related colonies, which historically was used to divide a larger region into smaller administrative divisions. The equivalent term in Swedish is (in Uppland als ...

Scania Scania ( ), also known by its native name of Skåne (), is the southernmost of the historical provinces of Sweden, provinces () of Sweden. Located in the south tip of the geographical region of Götaland, the province is roughly conterminous w ...

. It has been suggested that Kalmargården served as a seasonal residence for the royal family based in Old Lejre. Some of the historic evidence is on exhibit at Kalundborg Museum in

Kalundborg Kalundborg () is a Danish city with a population of 16,659 (1 January 2025),National Museum of Denmark The National Museum of Denmark (Nationalmuseet) in Copenhagen is Denmark, Denmark's largest museum of cultural history, comprising the histories of Danish and foreign cultures, alike. The museum's main building is located a short distance from S ...

Copenhagen Copenhagen ( ) is the capital and most populous city of Denmark, with a population of 1.4 million in the Urban area of Copenhagen, urban area. The city is situated on the islands of Zealand and Amager, separated from Malmö, Sweden, by the ...

. There is a visitor center near the Viking magnate's former residence; Fugledegård visitor centre. File:Fugledegård 9.jpg, Fugledegård visitor centre on the western lakebrinks. File:Tissø 4.JPG, Part of the Kalmargård excavations at Fugledegård. File:Tissøfynd 3.JPG, Some of the excavated artifacts from Kalmargård.

Nature

Even though Tissø is steadily polluted by excess nutrients from the surrounding farmlands and inflows, the environmental standard of the lake is usually considered good, because of the high rate of water exchange and an effective natural oxygenation of surface waters. Therefore, the lake supports a rich fish and plant life, with around 20 species of fish living here. Most of the fish are spending their entire life in the lake, but a few, like the ide and the

brown trout The brown trout (''Salmo trutta'') is a species of salmonid ray-finned fish and the most widely distributed species of the genus ''Salmo'', endemic to most of Europe, West Asia and parts of North Africa, and has been widely introduced globally ...

, migrates from the sea through the stream of Nedre Halleby Å. Surprisingly, the lake also houses

European flounder The European flounder (''Platichthys flesus'') is a flatfish of European coastal waters from the White Sea in the north to the Mediterranean and the Black Sea in the south. It has been introduced into the United States and Canada accidentally th ...

. The flounder can live in the fresh waters of the lake, but they cannot spawn here.Fugledegård at Tissø
Danish Nature Agency 2004 Tissø formerly supported commercial fishing, but is now exclusively fished by anglers only. Fishing is strongly regulated nowadays, requiring a fishing licence and is restricted to the daylight hours more than 100 m from the shores. Two larger areas of the western part of the lake, is also to be protected from both fishing and sailing, and rules apply to what size and kind of fish can be caught. According to the angling association 'Lystfiskeriforeningen Anno 1886', the lake is dominated by

European perch The European perch (''Perca fluviatilis''), also known as the common perch, redfin perch, big-scaled redfin, English perch, Euro perch, Eurasian perch, Eurasian river perch, Hatch, poor man's rockfish or in Anglophone parts of Europe, simply the ...

, but a good sized population of

northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (pikes). They are commonly found in brackish water, moderately salty and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). T ...

is here as well. Other common fish includes

tench The tench or doctor fish (''Tinca tinca'') is a freshwater, fresh- and brackish water, brackish-water fish of the order Cypriniformes found throughout Eurasia from Western Europe including Great Britain, Britain and Ireland east into Asia as far ...

, various

carp The term carp (: carp) is a generic common name for numerous species of freshwater fish from the family (biology), family Cyprinidae, a very large clade of ray-finned fish mostly native to Eurasia. While carp are prized game fish, quarries and a ...

s and

European eel The European eel (''Anguilla anguilla'') is a species of eel. Their life history was a mystery for thousands of years, and mating in the wild has not yet been observed. The five stages of their development were originally thought to be differe ...

. There is a small and fragile population of

zander The zander (''Sander lucioperca''), sander or pikeperch, is a species of ray-finned fish from the Family (biology), family Percidae, which also includes perch, Gymnocephalus, ruffe and Darter (fish), darter. It is found in freshwater and brackis ...

Birds

Tissø is home to a rich and varied birdlife and occasionally hunting

white-tailed eagle The white-tailed eagle (''Haliaeetus albicilla''), sometimes known as the 'sea eagle', is a large bird of prey, widely distributed across temperate Eurasia. Like all eagles, it is a member of the family Accipitridae (or accipitrids) which also ...

s or

osprey The osprey (; ''Pandion haliaetus''), historically known as sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor, reaching more than in length and a wingspan of . It ...

s can be seen – a rare sight in Denmark.Be close to white-tailed eagles
Danish Nature Agency On the lake itself

great crested grebe The great crested grebe (''Podiceps cristatus'') is a member of the grebe family of water birds. The bird is characterised by its distinctive appearance, featuring striking black, orange-brown, and white plumage, and elaborate courtship displa ...

common merganser The common merganser (North American) or goosander (Eurasian) (''Mergus merganser'') is a large sea duck of rivers and lakes in forested areas of Europe, Asia, and North America. The common merganser eats mainly fish. It nests in holes in trees ...

, various dabbling and

diving duck The diving ducks, commonly called pochards or scaups, are a category of duck which feed by diving beneath the surface of the water. They are part of Anatidae, the diverse and very large family that includes ducks, geese, and swans. The diving ...

greylag goose The greylag goose (''Anser anser'') is a species of large goose in the waterfowl family Anatidae and the type species of the genus ''Anser (bird), Anser''. It has mottled and barred grey and white plumage and an orange beak and pink legs. A lar ...

bean goose The bean goose is a species complex of goose that breeds in northern Europe and Palearctic, Eurosiberia. It has at least two distinct varieties, one inhabiting taiga habitats and one inhabiting tundra. These are recognised as separate species by ...

Canada goose The Canada goose (''Branta canadensis''), sometimes called Canadian goose, is a large species of goose with a black head and neck, white cheeks, white under its chin, and a brown body. It is native to the arctic and temperate regions of North A ...

mute swan The mute swan (''Cygnus olor'') is a species of swan and a member of the waterfowl family Anatidae. It is native to much of Eurasia, and (as a rare winter visitor) the far north of Africa. It is an introduced species in North America, home to ...

whooper swan The whooper swan ( /ˈhuːpə(ɹ) swɒn/ "hooper swan"; ''Cygnus cygnus''), also known as the common swan, is a large northern hemisphere swan. It is the Eurasian counterpart of the North American trumpeter swan, and the type species for the genu ...

, tundra swan and

Eurasian coot The Eurasian coot (''Fulica atra''), also known as the common coot, or Australian coot, is a member of the rail and crake bird family, the Rallidae. It is found in Europe, Asia, Australia, New Zealand and parts of North Africa. It has a slaty-bla ...

are usual residents. The beach meadows and

reed bed A reedbed or reed bed is a natural habitat found in floodplains, waterlogged depressions and estuaries. Reedbeds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. As ...

s house many foraging and breeding birds like pied avocet,

little tern The little tern (''Sternula albifrons'') is a seabird of the family Laridae. It was first described by the German naturalist Peter Simon Pallas in 1764 and given the binomial name ''Sterna albifrons''. It was moved to the genus '' Sternula'' whe ...

, common reed bunting,

Eurasian reed warbler The common reed warbler (''Acrocephalus scirpaceus'') is an Old World warbler in the genus '' Acrocephalus''. It breeds across Europe into the temperate western Palaearctic where it is migratory, wintering in sub-Saharan Africa. It is also a re ...

and

western marsh harrier The western marsh harrier (''Circus aeruginosus'') is a large harrier (bird), harrier, a bird of prey from temperate and subtropical western Palearctic, Eurasia and adjacent Africa. It is also known as the Eurasian marsh harrier. Formerly, a numb ...

in addition to Eurasian bittern,

bearded reedling The bearded reedling (''Panurus biarmicus'') is a small, long-tailed passerine bird found in reed beds near water in the temperate zone of Eurasia. It is frequently known as the bearded tit or the bearded parrotbill, as it historically was beli ...

, Eurasian penduline tit and

common grasshopper warbler The common grasshopper warbler or just grasshopper warbler (''Locustella naevia'') is a species of Old World warbler in the genus ''Locustella''. It breeds across much of temperate Europe and the western Palearctic. It is bird migration, migrator ...

. Almost all of the lakeside is on private hands, but there is a publicly accessible birdwatching tower near Fugledegård. Both the lake and the associated reed beds are of international importance to migratory birds, so hunting and ordinary traffic is strongly regulated in the eastern section.Tissø
Danish Nature Agency

Plants

On the southeastern shores near the village of Sæby is a protected strip of land consisting of dry

commons The commons is the cultural and natural resources accessible to all members of a society, including natural materials such as air, water, and a habitable Earth. These resources are held in common even when owned privately or publicly. Commons ...

on steep slopes, where human traffic is prohibited from 1 April to 15 July. The protection safeguards a special plant life here, breeding birds and the general view of the lake. North of this strip is a small

deciduous forest In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, after flo ...

known as Klinteskoven, with public access to the lake shores. The steep slopes at Tissø's northern end is also to be protected. Here sunloving plants like small pasque flower, sunrose and dwarf everlast are found, with the rare and threatened fragrant scabious in between. The

meadow A meadow ( ) is an open habitat or field, vegetated by grasses, herbs, and other non- woody plants. Trees or shrubs may sparsely populate meadows, as long as they maintain an open character. Meadows can occur naturally under favourable con ...

s below the cliffs are also of botanical interest, supporting plants like marsh lousewort, bog-star and various true sedges like blue sedge along with orchids like early marsh orchid,

western marsh orchid ''Dactylorhiza majalis'', or the broad-leaved marsh orchid, is a terrestrial Eurasian orchid. Subspecies include the western marsh orchid (''Dactylorhiza majalis'' subsp. ''occidentalis'') and southern marsh orchid (''Dactylorhiza majalis'' su ...

and marsh helleborine, in a

biotope A biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of flora (plants), plants and fauna (animals), animals. ''Biotope'' is almost synonymous with the term habitat (ecology), "habitat", which ...

of calcium-rich springs.

The nature park

The lake of Tissø is part of Naturpark Åmosen; a c. 8,000 ha

nature park A nature park, or sometimes natural park, is a designation for a protected area by means of long-term land planning, sustainable resource management and limitation of agricultural and real estate developments. These valuable landscapes are pres ...

consisting primarily of

Natura 2000 Natura 2000 is a network of nature protection areas in the territory of the European Union. It is made up of Special Areas of Conservation and Special Protection Areas designated under the Habitats Directive and the Birds Directive, respectiv ...

designations. Tissø itself belongs to Natura 2000 area 157 specifically.157 Åmose, Tissø, Halleby Å and Flasken
Danish Nature Agency

References

Sources and literature

* Gotfredsen, Anne Birgitte & Thomsen, L.G. (2011). ''Three pit houses at the magnate’s residence at Lake Tissø.'' In: Boye, L. (ed.) The Iron Age on Zealand. Status and Perspectives. Nordiske Fortidsminder, Series C, volume 8. København, pp. 211-220. * Jørgensen, Anne Nørgård, Lars Jørgensen & Lone Gebauer Thomsen (2011): ''Assembly Sites for Cult, Markets, Jurisdiction and Social Relations. Historic-ethnological analogy between North Scandinavian church towns, Old Norse assembly sites and pit house sites of the late Iron Age and Viking Period.'' Archäologie in Scleswig Sachsensymposium Haderslev 2010, pp. 95-112. * Bican, Josefine Franck, Anna Severine Bech and Susanne Klingenberg (2011)
Pre-Christian Cult Sites – archaeological inverstigations.
I: Hans Christian Gulløv, Peter Andreas Toft & Caroline Polke Hansgaard (red): Challenges and solutions. Northern Worlds – Report from workshop 2 at the National Museum, 1 November 2011, pp. 261-268. * Bican, Josefine Franck (2010)
Bulbrogård, the first aristocratic complex at Tissø - and a new approach to the aristocratic sites.
I: Gedächtnis-Kolloquium Werner Haarnagel (1907-1984). Herrenhöfe und die Hierarchie der macht im Raum südlich und ¨stlich der Nordsee von der vorrömischen Eisenzeit bis zum frühen Mittelalter und zur Wikingerzeit. 11.-13. oktober 2007, Burg Bederkesa in Bad Bederkesa. Niedesächsisches Institut für historische Küstenforschung (Hrsg.). Siedlungs- und Küstenforschung im südlichen Nordseegebiet 33, pp. 147-154, Rahden. * Thomsen, Lone Gebauer (2009): ''Pit Houses on Zealand in the Late Iron Age and the Viking period – a survey based on the material from the excavation at Tissø.'' I: Glaube, Kult und Herrschaft. Phänomene des Religiösen im 1. Jahrtausend n. Chr. in Mittel- und Nordeuropa. Hrsg.: Uta von Freeden, Herwig Friesinger, Egon Wamers. Kolloquien zur Vor- und Frühgeschichte Band 12, Frankfurt. Römisch-Germanische Kommission des Deutsche Arch. Instituts. Bonn, pp. 501-510. * Jørgensen, Lars (2008): ''Manor, cult and market at Lake Tissø.'' I Stefan Brink & Niel Price (eds.), The Viking World, Routledge/Oxon, pp. 77-82. * Jørgensen, Lars (2006): ''Tracking down the aristocracy. Distribution patterns and coin use at the Viking manor and market at Lake Tissø, Denmark.'' I: H.W. Horsnæs & J.C. Moesgaard (eds.): 6th Nordic Numismatic Symposium. Single Finds: the Nordic Perspective. Nordic Numismatic Journal 2000-2002, Copenhagen, pp. 190-207. * Jørgensen, Lars (2003): ''Manor and Market at Lake Tissø in the Sixth ti Eleventh Centuries: The Danish ”Productive” Sites.'' I: Pestell, Tim & Katharina Ulmschneider (red): Markets in Earley Medieval Europa. Trading and “Productive” Sites, 650-850. Macclesfield. pp. 175-207. * Jørgensen, Lars (2001): ''From tribute to the estate system, 3rd-12th century. A proposal for the economic development of the magnates’ residences in Scandinavia based on settlement structure from Gudme, Tissø and Lejre.'' I: Arrhenius, B. (red): Kingdoms and Regionality. Transactions from 49th Sachsensymposium 1998 in Uppsala. Theses and papers in Archaeology B:6. Stockholm, pp. 73-82. * Pedersen, Anne (2001): ''A Striding Mapn from Tissø – a rare imitation of Charlemagne’s Dorestad-coinage'' Nordisk Numismatisk Årsskrift 1994-96, pp. 22-40. * Jørgensen, Lars og Pedersen, Lisbeth (1996)
Vikinger ved Tissø. Gamle og nye fund fra et handels- og håndværkscenter.
(pp. 22-36) Nationalmuseets Arbejdsmark. København.

External links

Kalundborg Natur . Pictures of the lake.
Naturpark Åmosen
Homepage of the nature park and Fugledegård visitor centre {{DEFAULTSORT:Tisso Lakes of Zealand Archaeological sites in Denmark Prehistory of Denmark Iron Age Scandinavia Viking Age populated places Natura 2000 in Denmark