┌─Gerhard I Count of Holstein-Itzehoe
┌─Gerhard II Count of Holstein-Plön
┌─Gerhard IV Count of Holstein-Plön
│ │ ┌─Valdemar I of Sweden
│ └─Sofia of Denmark
│ ┌─Gunzelin III Count of Schwerin
│ ┌─Nikolaus I Count of Schwerin-Wittenburg
│ │ └─Margareta of Mecklenburg in Rostoc