indo-iranian heritage of “haft karšvar” in the old iranian and indian texts

geographical concept of “haft karšvar” could be traced back to the proto-indo-iranian period. after the separation of indians and iranians, due to geographical circumstances and religio-political changes, original indo-iranian narrative of seven part of the earth, turned into its current versions. a comparison of old iranian and indian texts, specially avesta and vīspā̊ŋhō  purāṇa, shows that in outline of original indo-iranian narrative, the earth was divided into seven parts which contained a central part surrounded by other six parts. in the middle of central land, there had been a heavenly mountain and a miraculous tree. in the beginning, amongst these seven parts which had been separated from each other by some obstacles, only central part was inhabited by mankind. after mankind’s divergence from the prototypical progenitor, the other six parts were also inhabited. in the avestan tradition – same as indian – due to climate conditions of eastern iranian plateau, original names of seven parts were replaced by the new ones. furthermore, it seems that from the perspective of older yašts composers, bactria was considered to be central part of the earth. afterwards, with the expansion of mazdaean religion and transmission of political center to the western part of iranian plateau, avestan concept of “haft karšvar” also changed. in the middle persian texts, since the central part was considered in the western iran, direction of the avestan western part was turned into the east and vis versa. the heritage of septet division of the earth, can be seen independently, also in the achaemenid sources which we can see a fading trace of septet division in the organization of achaemenid satrapies.