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Lilleborg today

Denmark · Ruin

Lilleborg

Lilleborg is a ruined 12th-century fortress located on a rocky hill in the Almindingen forest on Bornholm, Denmark, originally surrounded by the lake Borresø. Constructed as a compact royal stronghold, its principal surviving features are the oval curtain wall and the large square tower that defended the entrance.

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Photograph via Wikimedia Commons

First raised

1190

Its prime

1160

Today

Ruin

As it stood in 1160

What Lilleborg looked like in its prime.

Lilleborg in its prime (c.1160) occupied a 16-metre rocky island in Borresø, an oval stone plateau ringed by a low curtain wall that follows the cliff edge. A single large square tower about 9.5 metres across guarded the south entrance; masonry of coarse local stone with walls roughly 2.4 metres thick dominated the entrance. The enclosed interior measured approximately 76 by 41 metres and was reached by a wooden bridge and steep approach from the south.

Its story

The story of Lilleborg.

Lilleborg was raised in the 12th century on a rocky hill sixteen metres high in the Almindingen forest at the centre of Bornholm, at the time completely surrounded by the lake Borresø, and reached by a wooden bridge and a steep path. King Sweyn III wanted a seat of power of his own on the remaining fourth of the island, and of Denmark's 12th-century fortresses Lilleborg most closely resembles those of Saxon architectural style.

A square tower 9.5 metres on a side, with walls 2.4 metres thick, protected the entrance to a courtyard some 76 by 41 metres inside a curtain wall following the cliff tops. The fortress appears to have burnt down in 1259, when Prince Jaromar of Rügen stormed and destroyed the "king's stronghold" on Bornholm; once its defences were obsolete its stones were reused elsewhere, and restoration work ran from 2006 to 2011.

The hill was fortified long before the medieval castle: in 2025 researchers from the National Museum of Denmark and Bornholms Museum concluded that some form of fortification already stood on the site in the 4th century, remains of the Iron Age work having been discovered in 2010.

Step inside

6 places to explore in 1160.

The record describes 6 distinct spots at Lilleborg, including 1 interior: central courtyard of the oval plateau. Create your own photoreal reconstruction and explore every one, more scenes means more rooms, more angles, and more of the place to stand in.

South bridge and lake approachSteep approach path to the gateEntrance tower and gatewayCentral courtyard of the oval plateauWalkway along the curtain wallView from the opposite lakeshore

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Questions about Lilleborg

What is the history of Lilleborg?

Lilleborg’s history begins in the 12th century, when it was raised as a royal fortress and a seat of power for the king’s remaining territory on Bornholm. It appears to have replaced the larger Gamleborg nearby and most closely resembles fortresses of Saxon architectural style. In 1259, Prince Jaromar of Rügen stormed and destroyed the king’s stronghold; its stones were later reused, and restoration took place from 2006 to 2011.

What is inside Lilleborg?

Inside Lilleborg, the main surviving space is the central courtyard on the oval plateau. The enclosed interior measured about 76 by 41 metres, while the lower part of the entrance tower and foundations of other buildings also survive. The courtyard was enclosed by a curtain wall following the cliff tops.

Why was Lilleborg built, and what was it used for?

Lilleborg was built as a compact royal stronghold and as a seat of power on the part of Bornholm retained by the king. Its inland position made it easier to defend and suitable as a hiding place during sudden attacks, although it was not intended to protect the coastline. Later, when its defences were obsolete, its stones were reused elsewhere.

Where is Lilleborg?

Lilleborg is in the Almindingen forest in the centre of Bornholm, on a rocky hill close to the main road from Rønne to Svaneke. The site was originally surrounded by Borresø lake and lies in Bornholm regional municipality. Its position is inland rather than on the coast.

When was Lilleborg built?

Lilleborg was built in the 12th century. The site record gives 1190 as the year it was first raised, while the historical account describes its construction as taking place in the middle of the 12th century. It replaced the increasingly obsolete Gamleborg as a royal fortress.

Was Lilleborg ever attacked or besieged?

Lilleborg was attacked and destroyed in 1259 by Prince Jaromar of Rügen. The assault stormed the king’s stronghold and appears to have caused the fortress to burn down. Coins minted after 1259 have been found, however, indicating that it was inhabited after the attack.

What did Lilleborg look like in its prime?

In its prime, Lilleborg occupied a 16-metre rocky island in Borresø. An oval stone plateau was enclosed by a low curtain wall following the cliff edge, with a large square entrance tower about 9.5 metres across guarding the south entrance. The coarse local-stone masonry had walls roughly 2.4 metres thick, and the approach crossed a wooden bridge before climbing steeply to the gate.

Is Lilleborg still standing, or is it a ruin?

Lilleborg is now a ruin, with the oval curtain wall, the lower part of the entrance tower and foundations of other buildings surviving. Its stones were reused elsewhere after the defences became obsolete. Restoration work was carried out from 2006 to 2011, but the site remains classified as a castle ruin.

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