Abstract
The historical site of Qalat Mutabad in Piranshahr is of paramount importance in numerous historical and cultural documents such as potteries and brick architectural remains, especially in terms of architectural maps and plans. The existence of a star-shaped plan in the design of the site’s outer fence illustrates the importance and pivotal role of this area in the Piranshahr plain. The site is located beside one of the branches of the Little Zab (or Lower Zab) River, which has been gradually destroyed due to the passage of time and the land-use change, “use as a military base in the contemporary period,” and currently the evidence of the architectural debris of the building at the site is evident. Examples of star-shaped plan design in different parts of Iran, as well as European fortresses, can be observed, and it is comparable to the plan of Qalat Mutabad in this respect. The main problem of this article is to evaluate the site relying on the available documents and evidence so that we study the importance of military forts in the Piranshahr plain while achieving a relative dating of the site. Accordingly, some questions about the architectural structure, especially its plan and the military and residential function of the site arise. According to written historical sources, the study of similar examples, as well as material artifacts at the site level, hypotheses concerning the attribution of the site to the period after Safavid, “Afshar or Qajar,” military function inspired by Western architectural elements, are presented. This study was conducted in a historical, descriptive-analytical method. In addition to studying historical sources and field documentation by the authors at the site, aerial images and data gained from these images were exploited. 
Keywords: Qalat Mut-Abad, Form and Function Based, Star-Shaped Plan, Piranshahr.

Introduction
Qalat Mutabad site with an area of 20 hectares is located in Piranshahr city, 15 kilometers away from Tamrchin border crossing in south of Little Zab River. The plan of the site is star-shaped, overlooking the border crossings. In terms of architectural plan and location, Qalat Mutabad is noticeable and worthy of study.
Significance and Objectives of the Research: Concerning the destruction of the site and the ever-rising expansion of degradation factors, while introducing and recognizing Qalat Mutabad due to the lack of historical and archaeological data of the Islamic periods in Piranshahr, this study can contribute to the completeness of the information.
Questions and Objectives of the Research: Qalat Mutabad belongs to which period? What are the factors affecting the construction and star-shaped design of the site? It seems that this site belongs to the late centuries of Islam. Due to its geographical location and exposure to natural and political boundaries, Qalat Mutabad was built as a fortress and military base to repel the attacks of the Ottoman state or local insurgency.
Methods: The research method in this article is historical, and content analysis is descriptive-analytical. Aerial images explore written historical evidence and archaeological findings.
Literature Review: The historical site of Qalat Mutabad was pointed out in the photo book of Ali Khan Vali (Ali khan vali, 1862-1900: 183). In archaeological investigations, the Qalat Mutabad site with a history of 2500 BC, registration No. 611, was recorded in 1966 (West Azarbaijan Cultural Heritage Archives: 2019). The survey carried out in 2002 reviewed the site of Qalat Mutabad, and the area with historical-Islamic antiquity was registered as the hill of Qala-e-Mut with registration No. 7526 (West Azarbaijan Cultural Heritage Archives: 2019). In the study of Ali Binandeh for the master’s thesis “Archaeological Study of the Little Zab River,” he attributes this site to the Bronze Age, historical and Islamic period (Binandeh, 2008: 73).

Qalat Mutabad
Qalat Mutabad faces multiple problems, including the use of the site as a military base until recent years, industrial workshops in the area and boundary of the site, destruction by agricultural land, construction of garden houses, and the activities of unauthorized diggers. Problems have caused the site to lose its architectural structure and identity. For a detailed study, by utilizing satellite images of the Corona satellite taken in 1969, the site and its architectural structure are initially studied. Using the pictures of Ali Khan Vali’s book, a more accurate study of the site and its architectural evidence will be then addressed.
Below is the recorded photo, taken by Ali Khan Vali in the Qajar period, in which the word Qala-e-Mutabad was exploited. In addition to demonstrating that the site is a fortress, this historical document proves that the name of Mutabad has not been newly known in this area and has historical and old roots (Ali Khan Vali, Ibid: 183). The term Qalat in the Kurdish language means fortress, and it seems that Mutabad has come from the two words Mut + Abad. According to the evidence, before Iran’s Islamic revolution in 1978, there was a village called Motabad, which was evacuated after using the site as a military base in 1978 (Binandeh, Ibid: 73).
In Corona satellite images, the site has two parts of the outer fence with a star-shaped plan and the area’s inner part as a hill with a natural bed. There is a hill with a natural bed in the interior of the site. In unauthorized excavation cuts performed in the site, the thickness of ancient layers up to 2 meters is visible. Based on the Corona satellite images, an almost square-shaped area with suspicious architectural features can be seen at the top of the site.

Conclusion
Due to enjoying environmental potentials and also being located in the border strip of Iran with Mesopotamia, the Piranshahr region has always been a buffer zone due to successive wars from the Safavid period onwards with the formation of Safavid and Ottoman rules. With the coming to power of the Safavids and due to various gaps, local powers such as the Bilbas Tribal Union, the local governments of Savojbolagh Mokri and Urmia in Iran, as well as the local government of Baban in the Ottoman-ruled areas of Sulaimaniyah in Iraq, have turned the Piranshahr area into a scene of regional battles for various political, religious, and ethnic reasons. Historical documents and texts provide concise and beneficial information about the political and military situation in the Piranshahr area. Regional conflicts and wars mainly exhibit the military importance of the region and efforts to rule in it. About the existence of pottery findings and architectural works in the site of Qalat Mutabad and the lack of accurate dating of these findings because of their simplicity and locality, achieving a final decision based on the findings of pottery is impossible. Due to the existence of Corona satellite images and the intactness of the star-shaped plan of the Qalat Mutabad site and the presence of a photo of the site from the Qajar period and naming the site as the fortress, as well as the soundness of parts of the wall, towers, and architectural works in the photo, we can argue that not much time has elapsed since the destruction of the fortress. Accordingly, with comparative studies, the state of the landscape of the site and also the existence of similar examples of military fortresses with regular and star-shaped plans in the post-Safavid period “Afsharieh or Qajarieh” which are made inspired by European elements, the site of Qalat Mutabad can be attributed to Afsharieh or Qajar era.

Abstract
Mehr-Narseh is known as one of the most important character of the middle Sassanid era. Based on the written historical sources, the construction of some buildings has been attributed to him, among which the most outstanding ones are five fire-temple monuments built in the southwest of Fars. Although various theories have been put forward regarding the location of the structures, by far, the nature and qualitative value of them are unknown. In this study firstly, the political-religious personality of this Sassanid minister in various ways was investigated, then besides recognizing their religious nature and value via analysis of the sources related to Mehr-Narseh fire temples, the Chahar-Taqis attributed to him was also studied, according to the current theories,  so as to reveal some features of  the religious architecture of Sassanid era. This is a fundamental or basic research, and the nature and method of which is historical and descriptive-analytical. The data is also collected from library and fieldwork. Based on the results of this study, it seems that the fire temples built by Mehr-Narseh included two separate types and four fire temples attriuted to him located in Abruwān area were related to family fire meaned “Dādgāh”. According to the field studies and similarity, the previous theories can be criticized and a new group of religious temple of Sasanian period in Farashband can be introduced that contains one or several fire temples, which are attributed to Mehr-Narseh. It seems that these kinds of fire temples have a complex plan with additional architectural and probably had a number of attendants to do the work related to the fire temple. Overall, this research can provide a correct understanding of the fire temples of “Dādgāh” Fire during the Sassanid period. This also provides a new grouping manner for such these temples and can be known as a pattern for reviewing of usage and religious value of other similar Chahar-Taqis.
Keywords: Mehr-Narseh, Fire Temple, Chahar-Taqi, Sassanid Era, Dādgāh Fire, Farashband.

Introduction
One of the important points mentioned in the historical resources is the information regarding the personality of Mehr-Narseh, as one of the significant figures of the middle Sassanid period, who built several fire temples and made other services in several other fire temples, which has been attributed to him by the order of the Sassanid emperors. Discovering the fire temples constructed under the order of Mehr-Narseh has been one of the most interesting study topics related to the religious architectures of the Sassanid period during the last century. There are different theories regarding the probable location of the fire temples attributed to Mehr-Narseh, which mainly include the region between the current Kazerun, Farashband, Dehram, and Firouzabad. This article attempts to study the fire temples attributed to Mehr-Narseh from a different perspective. In the first step, we study and explore Mehr-Narseh character to determine his political position in the middle of the Sassanid period and have an idea of his religious position in the system. The second step is to survey the nature and characters of the fire temples attributed to him from in terms of the quality value and their positions, to have a final analysis of their architectural complexities. The main question of this study is the religious quality of the fire temples attributed to Mehr-Narseh and what kind of fire was kept in the fire temples attributed to him? Also, based on the fires kept in these fire temples, what is the level of architectural complexity of the mentioned structures? The proposed hypothesis for this question is that it is possible that the four fire temples of Mehr-Narseh were containing the fire of “Dādgāh” and the fire temple of Jereh contained the fire of Ādarān. It is also assumed that the Dādgāh fore temples of Mehr-Narseh had additional spaces in the form of small architectural complexes. Based on the purpose of the study, this is basic research and from the perspective of nature and methodology, the study is conducted via the historical and descriptive-analytical method. The data collection method was library study and fieldwork. Initially, the political and religious figure of  Mehr-Narseh was analyzed and studied, with the help of the written sources related to him or the fire temples attributed to him, to reach understanding about the nature of his fire temples through a comparison between his character and the characteristics of the fire temples attributed to him. The next step was the archeological surveys in the fieldwork alongside the library researches and evaluating the archeological documents and reports about the proposed Chahar-Taqs for the location of the fire temples attributed to Mehr-Narseh, from an architectural perspective to finally reach a suitable point of view about the architectural and religious quality of the fire temples attributed to Mehr-Narseh.

Discussion
According to Pahlavi and Islamic sources, Mehr-Narseh, the minister of the Middle Sassanid period, has attained his highest religious official during the reign of Bahram V, as the honored titles of the servant of the two fire temples, since in the “Matigan-i Hazar Datistan” there is no mention of him being resented by Bahram V. During the reign of Yazdgerd II and Pirouz, he and his wife were sentenced to be the “Ādurwaxšīh” or tending the fire of the temple fire, due to a sin that some researchers associated with Zurvanism. The religious dedication of Mehr-Narseh resulted in the construction of several public buildings in the provinces of Ardashir-Khwarrah and Shapur –Khwarrah and also four religious temples on his ancestral lands for himself and his three sons, which were run by his heirs until the first centuries of Islamic period; these fire temples were shires dedicated to the “Atash-e Dadgah”. Based on the archeological findings and the presented theories, the remains of the three Chahar-Taq of “Malik”, “Tall-i Djangi”, and “Khurma yak” can be identical with one of the four fire temples belonging to Mehr-Narseh, as well as to match the information provided in written historical sources. Meanwhile, the site of “Pir-e Jeyran” may also be considered as the fourth fire temple of Mehr-Narseh in Abruwān. Based on the comparison studies of the archaeological evidence and the written sources, it can be concluded that during the Sassanid period, the shrines associated with the fire Dādgāh, could be very magnificent according to the financial conditions and social status of its founder and have donations such as gardens and farmland, and their revenues were spent for the happiness of the soul of the founder. Such fire temples were also run by a person named “Sallar” or the guardian who was chosen by the founder of the fire temple, and this responsibility was transferable to their heirs. The existence of such a title could indicate that other people also served in these private fire temples, and therefore this category of family fire temples, like the fire temples associated with the “Behrām” and “Ādarān” fires, could have hierarchical complexities in terms of the number of servers.

Conclusion
Based on the results of this study, it seems that the fire temples built by Mehr-Narseh included two separate types and four fire temples attriuted to him located in Abruwān area were related to family fire meaned “Dādgāh”. According to the field studies and similarity, the previous theories can be criticized and a new group of religious temple of Sasanian period in Farashband can be introduced that contains one or several fire temples, which are attributed to Mehr-Narseh. It seems that these kinds of fire temples have a complex plan with additional architectural and probably had a number of attendants to do the work related to the fire temple. Overall, this research can provide a correct understanding of the fire temples of “Dādgāh” Fire during the Sassanid period. This also provides a new grouping manner for such these temples and can be known as a pattern for reviewing of usage and religious value of other similar Chahar-Taqis. Before this, no specific structure for the fire temples related to the fire of “Dādgāh” in the Sassanid period, had been introduced, and the only available evidence was about the findings in “Tull-i Sifidak” which has a cruciform architectural space beside the residential context, as a sacred place for the fire. Based on conducted analyses of this study, it is possible to categorize the different types of religious architectural structures dedicated to the fire of “Dādgāh” into two groups: The first type was the buildings that include a cruciferous space attached to their residential section, that might have simpler procedures and endowments. The second type was complexes including Chahar-Taq and interconnected architectural spaces, which were probably built in the endowed properties of the fire temple, including gardens and agricultural lands, and belonged to people with high social ranks in the Sassanid society, such as Mehr-Narseh fire temples.