# Olsborg

- **Country:** Norway
- **Condition:** Ruin
- **Location Text:** Tanum Municipality (now in Sweden)

Olsborg Castle, also known as Olofsborg, is a ruined fortification situated on a steep cliff within Tanum Municipality in the Bohuslän region of Sweden. Originally constructed in 1502 by the squire Nils Ragvaldsson, the structure was built as a strategic military response to recent rebel attacks originating from nearby Viken in Norway. While the site may have served as an early hill fort prior to this date, its formal development into a castle marked a significant moment in the region's defensive history during a period of intense Scandinavian conflict.

The castle possesses a turbulent historical narrative defined by repeated destruction and reconstruction. Shortly after a brief ceasefire in 1504, forces under King Hans of Denmark attacked and largely destroyed the fortress during a Christmas party. Following the political turmoil surrounding the dethronement of Christian II of Denmark, Swedish nobles Lars Siggesson and Ture Jönsson administered the area from the reconstructed Olsborg between 1523 and 1525. However, the site faced its final demise in December 1531 when Norwegian forces demolished both Olsborg and the nearby Karlsborg Castle during Christian II's attempt to reclaim his throne.

Despite subsequent efforts by Swedish monarchs Eric XIV and John III in the late 16th century to rebuild the stronghold, these initiatives proved unsuccessful, leaving Olsborg in a permanent state of ruin. The remains were clearly visible into the early 20th century and were subsequently excavated by the prominent archaeologist Wilhelm Berg. Today, the site stands as a historical landmark representing the volatile border disputes between Sweden, Norway, and Denmark during the early modern era, with its remnants categorized among the significant ruined castles and hill forts of Västra Götaland County.

![Photo of Olsborg](https://upload.wikimedia.org/wikipedia/commons/8/89/Olsborg.JPG)

**Source:** https://en.wikipedia.org/wiki/Olsborg_Castle (Wikipedia, CC BY-SA)