Babak Khorramdin
Pāpak Fort () or Babak Castle (), ″Ghal’eh-e  Baz″ is a large citadel on the top of a mountain in the Arasbaran forests, 50 km from Ahar, one parasang from Ardabil, 6 km southwest of Kalibar City in northwestern Iran. According to Ibn al- Nadim, it was the stronghold of Javidhan and Babak Khorramdin, the leaders of the Khurramites in Iranian Azerbaijan who fought the Islamic caliphate of Abbassids. The fort was conquered and ruined by Afshin′s army on 837.