The Otto Adelheid Pfennig (OAP) was a German coin type bearing the names of Emperor Otto III of the Holy Roman Empire and his grandmother Adelaide of Burgundy (Athalhet), which was minted soon after 983 as a regional pfennig in the Harz region. Minting took place at more than one mint in the area between Hildesheim and Quedlinburg and lasted unchanged until the middle of the 11th century.[1]
- ^ Otto-Adelheid-Pfennig at museum-digital.de. Retrieved 28 May 2022.