The toponyms used to name a large area in ​​the western half of Iran, from the fall of the Sassanids to the rise of the Safavids, experienced many changes in the social and political-administrative arena, and were reflected in different ways in the writings produced at this point. In Islamic historiography, these toponyms were also used alternately, and historians used them to address the geographical area they were considering. The main question of the upcoming research is how the names Jebal, Qohestan and Iraq-e Ajam appeared in various historians' writings and how they were used. The research approach of this article is based on thick description. The research findings indicate that in the opinion of Islamic historians, Jebal (approximately) was used as a common toponym for a wide area in ​​the western half of Iran in the third century. Gradually and without having a specific definition and limitation, it became popular in all kinds of historical writings and replaced the ancient toponyms of the region such as Mah and Pahle, but in the next century, due to the political developments in the region and the importance of some cities such as Ray and Isfahan, the city became central to the attitude of many Historians prevailed and did not allow Jebal to spread as a common toponym. Also, the name Qohestan, which was the Persian translation of Jebal, became popular in Persian writings at this time and added to the confusion. In the sixth century, the toponym of Iraq-e Ajam, gradually made its way in the writings of historians; But due to the flourishing of general historiography in the 8th and 9th centuries of Hijri, which were provided based on the sources of the third to the sixth century of Hijri, the toponyms of Jebal and Qohestan, while they were almost forgotten in the social and political-administrative arena, also came to life in the writings of Persian historians. They continued, of course, the historians of Egypt and the Levant were largely left out of this mess.

The city of Shirvan or Sirvan was one of the important cities of Pahle or Jibal during and pre-Sasanian era, which was considered the center of Masbadhan province. Masbadhan is the same Masabatike of Achaemenid, Seleucid and Parthian times, whose people played a significant role in regional and extra-regional equations and had an independent government. It is assumed that it covered a vast territory which increased or decreased over time. At present, we don’t know much about the state of this province. Nevertheless, with the availed background, along with its strategic location, it is attributed to the Sasanian period, and its cities were Shirvan and Ariyohan. Shirvan continued to serve as the center of this province along with other cities. Shirvan in the Sasanian era and during the first three centuries after the fall of the empire, still maintained it’s political, economic, and social importance and played key role in the developments of this era. As such, most geographers, Muslim historians and travellers, archaeologists visited this city and wrote enormously about the city, its inhabitants and architecture. In this article, an attempt is made to examine the historical geography, urban planning and architecture of this city and its role in sociopolitical and economic developments based on existing sources.