Frederick was provisionally declared king on 26 March 1523, which was confirmed at Roskilde on 5 August. After a siege that began on 10 June 1523, Copenhagen surrendered to [his forces on 6 January 1524, see https://danmarkshistorien.dk/vis/materiale/christian-2-1481-1559/
Christian 2., 1481-1559, regent 1513-1523"], danmarkshistorien.dk.
denstoredanske.dk
"Hans Tausen". Den Store Danske. Retrieved August 15, 2016.
"Kong Hans". Diplomatarium Norvegicum. Retrieved August 15, 2016.
wikisource.org
de.wikisource.org
"Adolf, Herzog von Schleswig-Holstein". Adolf I. (Herzog von Schleswig-Holstein-Gottorf). Allgemeine Deutsche Biographie. Allgemeine Deutsche Biographie. 1875. p. 111. Retrieved August 15, 2016.