In 1315, in alliance with Eric, Valdemar gained Turku castle and Häme Castle together with their provinces, i.e. most of Finland, as well as Stockholm Castle, most of Uppland and Borgholm with Öland, as the result of their civil war against the king.
Only Borgholm and Ottenby are documented in early writings to have been Viking settlements along with Halltorp, although archaeological records show evidence of Vikings at a number of other locations on Öland: namely, Gettlinge, Alby and Hulterstad.