Refsholm was constructed at the beginning of the 1370 ´s on a small island on Krönsjön (sjö = lake). It may have been built by the squire, later Sir, Harald Karlsson Stubbe. Harald was a good friend of King Albrekt of Mecklenburg and was a member of the Crown Council.
The fortress is situated on a hilly bank. At the top, one can still see the foundations of the dwellings of the lord of the manor, as well as the remains of both the hall and the tower. Other buildings have also been part of this establishment - there were houses for servants, craftsmen and guards. All this was built of wood. From this stronghold, Sir Harald controlled his land.
Refsholm lay where the army of Queen Margareta fought Albrekt ´s army. Probably the fortress was burned down by the troops of Queen Margareta in 1389. When archaeologists have investigated the site, they have found crossbow arrows and parts of coats-of-mail. In the lake, surrounding the island, there are a great many wooden poles. These have served as a barrier, to stop boats from mooring at the island. Some of these poles have been dated to the 1380´s.
The name of Refsholm was forgotten. Later, the manor was named Krönsborg.
Ivars Udde (Ivar´s point)
Opposite Refsholm, on the mainland, there is another a stronghold with banks and moats. It is called Ivars Udde. Possibly, it may have been established when Refsholm was besieged.