The family is first mentioned in 1258 with
Conradus and Hermannus Indagine (Latin for
Hagen meaning
hague, an area fortified and fenced with a hedge). From Hermannus an uninterrupted lingeage can be traced. The name changed from de Indagine to Hayn, then to Hagen and finally to Westernhagen. The lords of
Berlingerode in the
Eichsfeld district had already built the old moated Castle Hagen (Westernhagen Castle) near Berlingerode by 1123, although it is first mentioned in documents in 1288. Around 1300 some relatives, probably tribally related to the lords of Berlingerode, built Castle Osternhagen (Eastern Hagen) at
Hundeshagen. Some later members of this family named themselves after the old moated castle of Western Hagen after moving there. Westernhagen Castle was destroyed in 1525 during the
German Peasants' War. The main seat of the family then became nearby
Teistungen, which they had owned since 1283 and where they had built two
tower houses that were later replaced by manor houses. The family converted from Catholicism to Protestantism after the
Reformation in the sixteenth century. Members of the family served in the Prussian military under
Frederick the Great. In the twentieth century, most of the family properties were seized by the Communist government of
East Germany. After the
German reunification, the Oberhof manor and estate in
Teistungen was re-purchased by Burghard von Westernhagen, the father of
Princess Heinrich of Hanover. File:Teistungen Ortskern (6).jpg|Teistungen, Oberhof (Upper court) File:Teistungen Ortskern (5).jpg|Teistungen, Unterhof (Lower court) == Notable family members ==