┌─Baldwin I of Flanders
┌─Baldwin II of Flanders
│ └─Judith of Flanders ⇒
┌─Adelolf of Boulogne
│ │ ┌─Alfred the Great of Wessex ⇒
│ └─Ælfthryth of Wessex
│ └─Ealhswith ⇒
┌─Arnulf II of Boulogne
Arnulf III of Boulogne