Kungshamn-Morga naturreservat at Morgastugan vid Mälaren, Alsike socken, Uppland © Upplands Museum
Kungshamn-Morga Nature Reserve at Morgastugan vid Mälaren, Alsike socken, Uppland © Upplands Museum

Mälaren – the Heart of Svealand and Medieval Sweden

Mälaren near Stockholm my be a large freshwater lake. A thousand years ago, however, it was an open firth reaching from the Baltic into the fertile lowland of Central Sweden

He [Odin] himself went northwards to the sea, and took up his abode in an Island, which is called Odinsvi in Fyen.  Then he sent Gefjon north across the belt to the north to look for land. And she came to King Gylve, who gave her a plough-gate of land.  Then she went to Jotunheim, and bore four sons to a giant, and transformed them into a yoke of oxen.  She yoked them to a plough, and broke out the land and dragged it into the ocean right opposite to Odin’s.  This land was called Sealand. Afterwards, she settled there and dwelt. Skjold, a son of Odin, married her, and they dwelt at Lejre. Where the ploughed land was is a lake or sea called Lögaren.  In the Swedish land the fjords of Lögaren correspond to the headlands in Sealand. Brage the Old sings thus:

Gefion from Gylve drove away,
To add new land to Denmark’s sway
Joyful Gefion ploughing in the smoke
That steamed up from her oxen-yoke:
Four heads, eight forehead stars had they,
Gold gleaming, as she ploughed away;
Dragging new lands from the deep main
To join them to the sweet isle’s plain.

After: The Ynglinga Saga, or The Story of the Yngling Family from Odin to Halfdan the Black. In: The Heimskringla; or, Chronicle of the Kings of Norway: Translated from the Icelandic of Snorro Sturleson, with a preliminary dissertation. 3 Vol. Transl. by Samuel Laing. London 1844, Vol 1. p. 220 (minor corrections)


Topographical map of Mälaren
Topographic map of Mälaren showing the extent of the lowland around the lake. in the first mellenium most of dark green area consisted of flooded and swampy bogs (‘träsk’) and navigable inlets. Source: Lantmäteriet

Today, Mälern is the third-largest freshwater lake in Sweden. Until c. 1000–1200 it was an open firth navigated by Vikings, who were trading and pillaging on the shores of the Baltic. Likely this was the reason behind the foundations of Uppsala, Birka, Sigtuna and finally Stockholm. Centres, emporia, towns and cities, they left their successive marks on the history of Sweden from c. 500 – 1500.

Mälaren spans 120 km from the east to the west. It is bounded by the provinces or ‘landscapes’ of Uppland (to the northeast), Södermanland (to the south), Närke to the west, and Wästmanland to the northwest.

At the end of the Ice Age much of Scandinavia was covered in 3 km deep glaciers or ice sheets weighing down on the land below. When the ice melted and the weight was gradually lifted, the land below rebounded. At the same time, glacial floods, erosion and tidal waters left sediments covering the future landscape with more fertile topsoil than that which is encountered in the interior of Sweden. As the landscape lifted up, the fertile shores of the future lake and along the rivers feeding it, surfaced from the seabed. While the parts of the landscape, which are currently more than 150 metres above the sea surface were untouched by this process, lower-lying land was covered in a more or less fertile debris from the melting glaciers.

Out of these geological events, the Central Swedish Lowland was formed, spanning from the West Coast at Bohuslän to Stockholm. Inside this lowland, the large lakes – Vänern, Vättern, Mälaren and Hjälmen – lies in the middle of a fertile belt with Svealand to the north and Götaland to the south.

When the eastern part of the Swedish Lowland was created, the region presented itself with relatively low reliefs and altitudes, characterised by fertile soils. Before agricultural cultivation, broad-leaved forest of maples, oaks, ashes, lime and common hazel characterised the terrain. Later, this widespread forest came to represent an important element in the traditional type of husbandry supplying grazing forest, winter fodder, firewood, building material etc.

Until c. 1000, the future lake of Mälaren continued to be a navigable firth or bay in a seascape with at that time a five metres higher surface than today. The slow rebound of the landscape meant that inside the next 200 years, the firth however was effectually closed off tuning it from a brackish inlet to a fresh-water lake. When such central places as for instance Old Uppsala, Eskilstuna, and later Sigtuna were settled, they were all navigable from the Sea

The Mälaren Valley

The primary archaeological finds in the region date from the Early Iron Age and later. About 9400 grave fields are registered as well as several ancient fortified hills from this period. During the second half of the first millennium, the region experienced a shift in settlements from higher to lower ground, probably reflecting the new possibilities offered by the receding sea and the warming up of the climate after the downturn following the volcanic events in 536–41and the Justinian plague. A reduction of 75% of the farms in Uppland in the 6thcentury has been recorded. Following this contraction, it appears the survivors worked to establish themselves in new and more hierarchical social settings, forming an elite nucleus such as happened for instance at Valsgärde and Old Uppsala.

Old Uppsala, Birke, Sigtuna, and Stockholm

Medieval Sweden and its provinces
Medieval Sweden and its provinces

The latter settlement can be dated to c. 400 with several halls being superimposed upon each other. However, between c. 550 – 660, when people were probably still recuperating after the crisis, a whole new set of monumental building projects was setting their marks upon the landscape. Apart from the large burial mounds, we know of a 50 metre long hall, erected on a terrace, more terraces, large workhouses, two long processional roads and several other buildings. It is difficult not to see this building activity as part of the formation of a clearly stratified society with the presence of a distinctive upper stratum, an elite. Surrounded by large farms capable of producing a significant surplus of victuals, this site came to be thought of as the nucleus of future Sweden.

Later, Birka (c. 750 – c. 1000), the Viking Emporium came to act as the main trading centre, featuring a cosmopolitan and religiously diverse population, until Sigtuna was founded c. 970 – 80. Some have floated the hypothesis that the residents at Birka were transferred or moved to this new centre, but no direct evidence points in this direction.

Finally, when the entrance into the firth near Stockholm silted up in the 12thcentury, the new capital was founded to advance trade and commerce with the other fledgling nation-states and trading cities circling the Baltic. Former royal and sacred centres like Old Uppsala, Birka, and Sigtuna gradually lost their lure.




Mälarens Vattenrådsförbund


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