The progenitor of the family, Count Poppo I of Blankenburg (c. 1095 – 1161 or 1164) probably was related to the Rhenish Reginbodonid[1] dynasty of Archbishop Siegfried of Mainz (d. 1084), a cadet branch of the Franconian Conradines.

His uncle Reinhard of Blankenburg was Bishop of Halberstadt from 1107 onwards and provided him with large estates in the Eastphalian Harzgau region between the Ilse and Bode rivers.

After the deposition of the Saxon duke Henry the Lion in 1180, the Regenstein counts were temporarily arrested by the forces of Emperor Frederick Barbarossa, but were reconciled with the Hohenstaufen monarch soon after.

After a lengthy feud Heimburg Castle, built about 1170 by King Henry IV and soon after devastated during the Saxon Rebellion, was acquired by the Regenstein counts in the early 14th century.

These tales were romanticised in the ballad The Robber Count (German: Der Raubgraf) by Gottfried August Bürger, melodized by Johann Philipp Kirnberger and the novel of the same name by Julius Wolff.