ardashir khwarah, from establishment to fall on the basis of historical texts

the round city of ardeshir khwarah, with its concentric layout, can be considered as the first city which established by the founder of the sasanian dynasty as a symbol of the sasanian royal ideology. ardeshir khwarah plays a key role in establishment of sasanian sovereignty and urban planning. however, a little is known about the history of the city. it seems even stranger if we consider the reports of the early islamic geographers and historians, recording that the city was flourishing until 5th century a.h. now lots of questions can be posed about the city. what kind of information can be extracted from historical written sources concerning the reason and process of formation, thriving and abandonment of the city? in other word, how the city has changed during the transitional period from sasanian to islamic period? based on the historical sources, the present paper deals with the historical identity of the city and its spatial order and functional characters.