Since the 15th century, Flekkerøy was an important harbour along the
Skagerrak, and since 1540 it has been considered as the most important outport in the whole region of
Southern Norway. In 1555, the first fortifications were built, but it was torn down in 1561.
Anne of Denmark and
James VI of Scotland came to Flekkerøy in 1589. In the early 17th century, the harbour again became of strategic importance, and in 1635 the island was visited by King
Christian IV who decided to build the
Christiansø Fortress to protect the harbour. In 1656, the
Fredriksholm Fortress was built, and the Christiansø Fortress was abandoned. In 1807, about 250 people lived on the island. On 18 September 1807 during the
English Wars, a
Royal Navy squadron led by
HMS Spencer arrived on Flekkerøy and proceeded to
slight the disused Fredriksholm Fortress by blowing it up. Four British servicemen were killed in the explosion after they went to check on the powder barrels'
fuses. In 1848, a cannon battery was built, but in 1872 it was abandoned, and in 1874 the partially rebuilt Fredriksholm fortress was also closed down for good. In 2005, the remaining military properties on Flekkerøya were secured for public outdoor recreation by the Ministry of Climate and Environment. ==Politics==