Christiansøfarten

Visit the world’s first naval base and an impressive fortress dating from 1684. Take a day trip to the fortress islands of Christiansø and Frederiksø – Denmark’s easternmost point.

Ertholmene – a sought-after excursion destination

The Ertholmene archipelago lies on the horizon northeast of Bornholm. It consists of the two inhabited islands, Christiansø and Frederiksø, the bird sanctuary Græsholmen, and a number of larger and smaller skerries.

Once a collection of barren rocky outcrops rising from the sea, the islands have become a popular destination for visitors.

Experience the echoes of history

It began in 1684, when King Christian V of Denmark (1670–1699) decided that a defensive stronghold should be built for the navy’s ships in the Baltic Sea. Denmark had lost Scania, Halland and Blekinge in the Treaty of Roskilde in 1658, making it necessary to monitor the movements of the Swedish navy in the Baltic. A natural harbour lay between two of the islands, and this was where the fortress of Christiansø – the world’s first naval base – was built. The two distinctive towers, Store Tårn on Christiansø and Lilletårn on Frederiksø, were constructed first.

An impressive structure

Bastions and ring walls were built on both islands facing the open sea. Behind them lie the fortress’s many other buildings, part of an impressive structure developed throughout the fortress period. Danish naval vessels could seek shelter in the harbour, take on water and provisions, and repair damage sustained on Baltic voyages. The fortress of Christiansø was decommissioned in 1855, but it remains intact and tells an important chapter of Danish cultural history.

Life on Christiansø today

Today, the historic setting is home to a thriving small civilian community of about 100 residents. Christiansø has a school, church, lighthouse, post office, library, community hall, museum, campsite, grocery shop and inn, as well as its own fire and rescue service, power supply and waterworks.