Sæheim (Seim) at Lygrefjord is mentioned as one of the royal farms of Harald Hårfagre. Several of the first Norwegian national kings had their seat here, and the farm became Crown Property up to the 1400s. According to the sagas, Håkon den gode is buried on the farm.
At the southern end of the bridge between Radøy and Fosnøy archaeologists found an unusual Stone Age settlement. There was a thick “cultural layer” here with the remains of the waste dumps of a hunting people. The place was called Kotedalen. Here they came, one group after the other, and settled for some weeks, some months, or maybe years before they went on, leaving the settlement deserted. Time after time it happened. At least 16 settlement phases have been identified, stretching over 5,500 years.
The prehistoric site at Årbakkasanden with menhirs and burial mounds has been visited, described and illustrated by many learned researchers through the last 350 years. All the same, we still know very little of this unique cultural monument.