The island was divided into a Swedish and a Norwegian part until it was ceded from Denmark-Norway in 1658, by Treaty of Roskilde. The division continued in the official name of the provincial districts of Swedish and Norwegian Hisingen or "Svenska Hisingens härad" and "Norska Hisingens härad", until 1681 when they were renamed into the Eastern and Western districts.
See also: Islands of Sweden, History of Westrogothia, History of Bahusia