Abstract
The expanded territories of the ancient Iranian empires raise a question for the audience, at first glance, despite a display of authority and domination of the kings, that how the central governments extended their domination over these regions and defended it against foreign threats. In the wide Sasanian Empire, one policy of the emperors of the dynasty was to establish new cities and renew old ones to expand their dominance over the country. As a result of these efforts in which required the founding and reconstruction of intercity pathways for moving goods and troops, a vast network of cities and routes were gradually formed. In this network, cities had the role of nodes for controlling and providing the essential resources and supplies for the central government. Thus, it can assume that the network of cities, moreover expanding the dominance of the Sasanian government, also had affected their fall. This study aimed to find appropriate answers for this question, using library resources through a descriptive-analytical methodology that what role the communication network of Sasanian cities has played in the Arabs conquests. The result findings indicate that the vast communication network of the Sasanian cities has not only facilitated the Arabs troops’ movement and campaign, but they were also able to weaken the defensive power of cities through Blocking support routes. Moreover, The Arabs had been able to consolidate their occupancy and dominance by capturing the cities as network’s connection points.
Keywords: Sasanian, Arabs, Sasanian cities, Conquest, Communication network. 

Introduction
The concept of the realm can be defined by some individual domains played a source role for a central government interconnected via some access roads, and being protected from improvised border posts; however, each domain is surrounded by some enclosed areas not being purposed for settlement (Smith,2007:28-29). The ancient governments were modeled as some access networks to resources like cities, trade bases, or natural mines for their developed dominance based on the management of those charged operators in the controlled trades, taxes, infrastructures, law enforcement, and military proceedings (Smith,2005:835-836). In this way, the empire owns actually a communication network for transported goods and cities could be interlinked (Liverani,1988:86-92). Based on this model, the governors initially establish their authority over the most critical chosen resources, and subsequently, control the corridors and essential routes connecting the relevant domain to the imperial network system; so it is possible to construct some links as roads or canals from the new domain into other parts. Therefore, they can manage those realms with a high transformed economic and social data shown with their widespread control over the essential resources (Smith,2007:32-33). Facilitating the communication among various empiric sections, the Sasanian communication network plus their cities were widespread under the imposed state surveillance (Miri,2012:104). In the late period, monitoring the main network routes was assigned into the quadratic generalissimo (Spahbodān) of the Sasanian empire (Howard-Johnston,2012:125). It suggested a political and military significance of the network maintenance for the Sasanians, and according to Smith, after the intercity network of interaction finished, it was possible to collapse the states (Smith, 2005: 838). Given that the role of every Sasanian city was based upon certain matters and essentials, it is necessary to compare and analyze their effects in the fall of the Sasanian empire. The study findings are beneficial for those investigators of the historical urban background and the condition of traditional ancient Iran.
Therefore, this study aimed to evaluate the collapse of the Sasanian state and the Arab conquests based on the perspective of the network interconnection of Sasanian cities. The raised study question is that based on their status and place in the widespread network of Sasanian cities, what roles and effects had every Sasanian city placed along the routes of Arab conquests in this event? Library resources were used for data gathering in this descriptive-analytical study.

Network of Sasanian Cities and Roles in Arab Conquests
The Sasanians established their dominance policy based on the city developments and the necessity of their interconnection. Accordingly, surveillance of urban connection routes became essential for the state because of both military logistics and support and trade and revenue. That was highly important, especially in border regions and even some cities were established to support other cities in the frontlines (Liverani,1988:92). Besides the development of cities and communication routes, the states were considered the source access network with some defined regions and borders to be defended (Smith,2005:835). The potential danger of the Arabs made the Sasanians construct a defensive line of small military forts for surveilling important points in the communication network of the Mesopotamian plain (Howard-Johnston,2012:97-98). The Arabs used to violate the state frontiers. After the succession of Yazdgerd III, their motives increased for capture more areas after their progressive onrush into Iran’s territories (Tabari,2004:1587-1588). Intercity routes with a previous role for widespread Sasanian authority in Iranshahr cities were traversed by the Arabs and their troops to progress into the Persian central plateau (Tabari,2004:1959). Eastern Iran disconnected from the central cities after Rey’s capture (Frye,1977:12) as a critical route from the western cities to Khorasan (Nicolle,1996:12). Also, Zarang’s capture led to the disconnected Sistan-Khorasan due to the defeated highway of Zarang-Kirkuk-Herat (Ibn Huql,1987:158), and subsequently, Yazdgerd III was trapped in Khorasan (Farrokh,2013:92). Yazdgerd went to Marv city with special military strength and position in order to take back the monarchy, but Neishabour capture, the support military base, happened earlier by the Arabs (Bruner,2014:174). After the weakened defenses, the death of Yazdgerd III, and the peace of governor with the Arabs occurred in Marv city, the fall of the Sasanian dynasty was realized there.

Conclusion
The Sasanians expanded their authority through the developed urban centers and roads over their empire and then established strategic base points for land maintenance and protection. Due to the policy, cities like Neishabour in Khorasan or Mesopotamian Anbar were higher political and economic prominence over others being responsible for providing military and economic support to the surrounding cities. However, cities like Isfahan or Qazvin alongside Oboleh functioned as connection points and crossroads in the urban network, and sometimes, their removal meant simultaneous disconnection of several state routes from the control of the central government. Therefore, the Sasanians invested variously in building walls and ditches for cities’ protection, but political turmoil, civil wars in the late Sasanian period, and destructive effects of the long Byzantine wars overall weakened the defensive shield. Apparently, after invading Iran’s cities, the Arabs could use the joined Iranians to their armies, or the Iranian settled Arabs and identified well the routes and connection points of the cities, blocked the supply and support routes, and facilitated Iranshahr capture.

Abstract
In the traditional architecture of Shushtar, as one of the architectural types of Iran, there are examples of architectural regionalism approach. Houses decorated with motifs, designs and decorations, which have given a special glory to the architecture of this city with a combination of three materials, stone, plaster and brick. A small part of the patterns and decorations of these houses is in the entrance area of the main door, but most of the decorations and arrays are in the interior of the houses of this city. Most of these houses are known by the name of the owner or owner. One of these houses is “GhasabNejad” house. This house is a dominant example of Shushtar decorated houses. This research is done with the aim of getting to know better about the decorative elements and motifs of Shushtar city as an example of warm and dry regional architecture and at the end of the article, the question of what and why are the three decorative motifs and elements of Shushtar Butcher House, based on the critical regionalism approach The answer is given. The information of this article was collected in the field using visual and library evidence and presented in a descriptive and analytical way.
Keywords: Shushtar Traditional Architecture, Ghasabnejad House, Critical Regionalism, Anthology Networks, Brick and Stone Decorations.

Introduction
Shushtar is one of the old cities of Iran, where there are monuments from different historical periods. This city was prominent as the center of Khuzestan during the Qajar period and most of the existing works of residential architecture with decorative elements are attributed to this period. Among the important buildings of this city, we can mention the “Afzal” complex, the houses of “Marashi”, “Mustafi”, “Bakal-Sadat”, “Gazer”, “Qasabnejad” and the like. In addition to the specific and functional architecture, the mentioned buildings are decorated with arrays that stand out like a beautiful painting on the walls. Harmonious proportions, various visual elements including line, surface, volume and texture in combination with light and shadow, appropriate combination of components such as lungs, frames and borders, headers and the quiet whisper of change from pattern to frame and from frame to surface of some of these buildings. The city built something that the concept of well-formed calligraphy tradition can be applied to parts of these buildings. In the area surrounded by the two branches of the Karun River in Shushtar, the building studied in this research is GhasabNejad’s house. This building located in “Dol Dol (Moghi)” neighborhood is located in the vicinity of Gazer’s house and belongs to the Qajar period, which was renovated in 2016 under national registration number 29157 and at the end of 2016. This house consists of four floors, ground floor, first floor, Shabestan, and Shawadan. Due to its area, this house is one of the historical, large and highly decorated houses of Shushtar and has triple motifs of stone, plaster and brick. According to what has been said, the purpose of the current research is to study the types of motifs used in GhasabNejad’s house in order to better identify the historical houses of Iran, and finally to the question of what and why are the motifs and three decorative elements of Shushtar’s Butcher’s house, based on the approach of critical regionalism The answer is given. The discussion about the architectural and structural elements of this house, such as arches, columns and the like, is out of the scope of this research.

Theoretical foundations
Since this research focuses on architectural decorations, the three decorative elements of butcher houses are analyzed as an example of Shushtar houses, based on the approach of regional architects. Critical regionalism is a middle ground between the two, with regional preferences that are not identical to native architecture. From Frampton’s point of view, local cultures should be viewed in a way that is modern and has the ability to become modern. Achieving critical regionalism is the exploitation of local characteristics inside and outside the modern building form and does not mean returning to traditional building. Frampton calls this type of architecture, which resists the trend of homogenization of world architecture, as critical regionalism (Tadjdee and Islami 2018: 22, quoted by Frampton). In Table 1, the features of regionalist architecture are stated in terms of Islamic and modernism.

GhasabNejad’s house 
GhasabNejad’s house is one of the historical houses of Shushtar city, which is located in “Doldol (Moghi)” neighborhood, adjacent to “Gazer” house. This house, like most of the remaining traditional houses in this city, belongs to the Qajar period, which, in addition to the traditional architecture, has different decorative arrays. About the history of ownership of this house (Fig.  1) (Fig.  2) shows the plan of these two complexes. Currently, both parts of this historical house have been registered in the national register. The architect of this house is “Mohammed Taghi Mimarbashi Shushtri” according to the inscription that is located near the porch of its outer part (Gazar House) and the date of completion of the building is 1277 AH (photos 3).

Decorations of GhasabNejad house
GhasabNejad house has triple decorations of stone, plaster and brick. Brick patterns are like (Fig. 4). Another part of the decorations of the old houses of Shushtar is the butcher house of Setonah, which is built with materials such as stone and brick, and their decorations include the motifs of “Kartele”, “Baik” and “Congress” (Fig. 5). Plaster grids are among other motifs used in Shushtar houses, which are placed on the facade of the building and usually between the arches and above the windows. In addition to decorative use, these elements were used to ventilate the air and let light in. (Fig.  6). Fig. 7, shows the three decorations of GhasabNejad’s house. The stone decorations include animal and plant motifs, each of which has different meanings. (10) The location of the plaster grids is also shown. Also, pictures (11 and 12) show other brick motifs in the butcher’s house building.

Conclusion
Three elements, brick, stone and plaster, are the main materials of Shushtar architecture and its decorative arrays, which were used in GhasabNejad’s house with refinement and merit in the structure and decorations of the building. The materials, motifs, form and decorations are common in most Shushtar houses, with the difference that each architect has made changes in them according to the personal taste and interest or the opinion of the owner of that building. The stone carvings of the butcher’s house include animal motifs such as peacocks, parrots and plant motifs such as lotus flowers. The roles of these animals and plants are sometimes mythical and probably liked by the architect or owner of the building and according to the cultural conditions of that time and the owner’s financial ability. The motifs of Golchin Gachi networks are a combination of Islamic geometric Chinese knot motifs and its famous shamsehs, and one case is a combination of Chinese knot and cedar tree. The decorative brick motifs of this house are arranged on the top of the porch and the edges around it. There are three motifs, Serzi Sarbala (in the local language), on the top of the porches, and complex key armband motifs, and one, two, and three plains, are engraved on their margins. The technique of performing brick patterns above the porch is flat and their edges are highlighted. The pattern of the columns was from the Moqrans design shared by the houses of Shushtar, such as the pattern of Kartele, Congress and Beyk. Some roles have been named according to their resemblance to something else. Like the pattern of the head below the head, which is similar to the pattern of the mat.
The reason for the use of these decorations is to align with Shushtar’s traditional architecture and this feature is consistent with the regional preferences side of the critical regionalists’ approach in architecture. Following this tradition, there are brick patterns on the front of the porches and on the outside of the houses, stone patterns are on some of the gates, considering the structural function of the stone, and plaster grids are also implemented in the upper part of the building. Among the three elements used in GhasabNejad’s house, the patterns of the front bricks of the porches were functional, mostly decorative, and the stone carvings and plastered grids had both decorative and practical functions. In this building, in addition to the decorative function, these three elements have been used to express the spiritual, material or traditional interests of the owner of the property. Among the three mentioned elements, according to the long-standing media tradition, stones have always been the representation of the personal feelings of the architect or the owner of the building.
Relying on the approach of critical regionalism, it can be said that the stone element is a special functional and decorative element in the architectural structure of Shushtar city as well as GhasabNejad’s house, which makes the architecture of this city different even compared to its neighbor, Dezful. It originates from the stone bed of the city and the presence of stone mines near the city of Shushtar. It seems that the architects of Shushtar have taken advantage of their unique native and regional element in building in the right place. Also, perhaps the use of stone for personal expression reminds us that the oldest means of expressing human emotions in a space other than its original place, i.e. mountains and deserts in the man-made environment, is still capable of expressing human emotions. The tradition that started from the heart of the mountains, rocks and caves continued in the cemeteries and the like, and in public and private places, it has a dual function of structure and media.
  The adaptation of architectural elements, especially the triple arrays of GhasabNejad house as a relatively complete example of Shushtar’s traditional houses, showed that the architecture of this house is compatible with most of the features of the critical regionalism approach, despite the time difference and the youth of the critical regionalist architecture discussion with ups and downs. The use of stone in the building as a special local element and the presence of a parrot in the stone bearer inscriptions as a non-regional bird in this building are two important features of the critical regionalism approach that has been digested in Shushtar’s architecture.

In this article, I build on my earlier work, which places Manichaean missionary activity within a larger network of court activity from the Roman Empire to Tang China, in which ambassadors, as well as wandering sages and ritual specialists, spread knowledge about cultural difference. These interactions usually took part between neighboring principalities, but they were also enmeshed in the gradual spread eastward of Iranian Manichaeism across Central Asia. Various Manichaean accounts highlight the importance of teaching “wisdom” in the bid for support from local rulers. According to the Cologne Mani Codex, Mani meets an unnamed king, instructing him in wisdom, the Manichaean commandments, as well as the “two natures”. What fragmentary evidence we possess for the spread of Manichaeism to China suggests that it, too, proceeded largely through the activity of traveling sages across court networks. 

Abstract
Undoubtedly, the southern area of Tehran province, which has been formed in the fourth region over time, especially in the late Islamic centuries, based on historical sources; It was always of great importance for the governments of this era from the point of view of geographical and political location. One of the reasons for the importance of this area was its location on three important communication routes that connected Tehran to Qom. The above research was carried out with the objectives of identifying and documenting as well as understanding the formation and function of related facilities in the ancient roads located in the south of Tehran to Qom province, in which two questions are also raised: 1) the most important communication roads located in the southern part of the province What are the communication routes between Tehran and Qom? And 2) which pattern or patterns did the studied road network generally follow? Based on this and relying on historical written sources and archeological field studies, we can propose the following hypotheses: three important communication routes in the studied area, from the dimensions of road scenery [residence-welfare, security-guidance-movement scenery] which are a They were a coherent group, they obeyed. Routes that, apart from having (commercial and economic effects) Functions on the communities living in their neighborhood; they also had many effects on the (cultural and social relations) of these societies. The present research was done with descriptive-analytical method and gathering information in the form of documentary and historical studies and archeological investigations. The results of the present research indicate that three important communication networks [1) Abdul Azim Ray Gate - Kenargerd - Dier kechein - Qom, 2) Aliabad - Hoze Sultan - Qom (abandoned) and 3) Aliabad - Manzariyeh - Qom] in the southern region of Tehran province. It was located towards Qom in chronological order.
Keywords: Road Network, Tehran, Qom, Late Islamic Centuries, Archaeological Evidence, Historical Texts.

Introduction
Regarding the description and recognition of the ancient and communication routes from the south of Tehran province to Qom in the Islamic era, at the beginning with the center (Rey) and later (Tehran), there have been several historical and geographical documents that show that the communication routes The above in this area were of great importance for the governments of this period. Ibn Faqih, describing the main roads of Ray to the neighboring areas in terms of commercial nature, says: Goods were also produced by Ray artisans, they made crafts such as combs and salt pans, etc. from wood. Ray weavers were also famous worldwide and all kinds of They exported clothes to the eastern and western regions through the important roads of this city) (Ibn Faqih, 2000, 51). Moghdisi also writes about the roads of Ray from a (mobility-security) point of view: ((the easiest and most prosperous road in Iran is the road of Ray)) (Moghdisi, 1982: 718) and further says: it is clear that this feeling Comfort and security should be established for travelers so that they can easily take advantage of all the sights and facilities provided near the road (ibid., 574). Ibn Hawqal also paid attention to the Ray road from the (commercial nature) and in this context he says: Apart from Isfahan, which was a commercial and important city, from Iraq to Khorasan (Ray) can be mentioned, which is The reason for having different main and secondary ways in terms of production and export of goods is unique and significant (Ibn Hoqal, 1987: 106). Bakran considers the distance between Ray and Isfahan to be about 62 farsang (Bakran, 1963: 15) and Imam Shushtari, like Bakran, considers the distance between Ray and Isfahan to be 62 farsang (Imam Shoshtari, 1960: 35). Mostofi states that the distance between Ray and Isfahan is 86 farsang (Mostofi, 1983: 51). In the last few decades, our understanding of the above-mentioned communication routes relied more on the same historical documents. However, due to the abundance of archaeological evidence related to these routes, which included buildings and facilities related to them; In previous years, they have been studied and investigated by some researchers and archaeologists in the field, and these archeological evidences themselves support the first hypothesis in line with their alignment with the writings of historical-geographical texts and travelogues in the best possible recognition of communication routes. It illuminates between the two cities of Tehran and Qom.

Discussion
The southern region of Tehran province was considered as one of the key strategic and geographical regions during the late Islamic centuries. The existence of numerous buildings and intermediate structures in the three ancient routes of Tehran - Qom, shows the archaeological evidence and the importance of this region. As mentioned, this highway starts its route from the south of Tehran province and passing through the cities and villages located in this area to the city of Qom and from there, turning into several branches to other parts of the country such as Isfahan, Kashan, Arak and others. The southern regions are connected. One of the most important features of this highway is its (cultural and religious) dimension. The cultural and religious dimension of this course can be seen as the first option that was always considered by the rulers of the late Islamic centuries, especially Safavieh and Qajar. The reason for this importance was the existence of the holy court of Hazrat Masoumeh in the city of Qom. Therefore, this issue caused the rulers of the later Islamic centuries to build and erect numerous buildings and facilities on the way to the extent possible for the well-being of these pilgrims and caravans, and many of these buildings are still standing. Another importance of Tehran-Qom highway; It was connected with the Tehran-Khorasan highway, which along with this highway was also considered one of the cultural routes and thresholds of Iran’s nobility. The third strategic importance of the Tehran-Qom highway is the ((commercial)) dimension in the way that in the late Islamic centuries, this highway was a very important bridge for the exchange of commercial and commercial goods that went to Tehran and the north of the country through Bushehr port. were carried One of the other important issues that always add to the importance of the Tehran-Qom highway was the (political and military) dimensions, because the statesmen of the late Islamic centuries [Safavieh and Qajar] to advance their goals in these fields and reach the capital as quickly as possible. As well as the open waters through the Persian Gulf and the Oman Sea and on the other side of the Caspian Sea, they urgently needed a good route to achieve these goals, which has high levels of amenities and road-dependent facilities. Therefore, the existence of these mentioned dimensions has proved the special importance of the southern region of Tehran province.

Conclusion
Based on the questions and assumptions raised, as well as citing historical sources, archeological investigations and the analysis of these components together, we can reach the conclusion that the southern region of Tehran province due to its special cultural and political position that during the last centuries Islam has always been important from the rulers of this era, and on the other hand, categories such as trade brought the transfer of cultural and social experiences to the people living along these communication networks, and these communities themselves are somehow a part of this economic cycle. and were considered cultural. Therefore, the existence of these three important communication routes: 1) Abdul Azim Ray Gate - Kenargerd - Dier kechein - Qom 2) Aliabad - Hoze Sultan - Qom [abandoned] and 3) Aliabad - Manzariyeh - Qom, which also followed the patterns of Manzariyeh Road. The importance of this area is increasing. so, from the archaeological evidence that included buildings and intermediate structures [caravans and bridges], he also acknowledged that the studied routes were always the place of traffic and passage of many commercial caravans and travelers. However, several reasons can be imagined in the field of recognition, formation and functioning of these communication ways and the buildings and structures located in them: 1) the history and long history of the territory of southern Tehran province in the creation of roads and facilities related to them. 2) Two factors of preparation of main roads and provision of comfort facilities and safety of travelers and caravans ((road monitors)) which were realized by completing road construction and construction of intermediate buildings: a) establishment of caravanserais and shelters. b) Creating water structures and solving problems of lack of water in these routes (reservoirs and glaciers). c) Establishing security and guarding caravans and passengers. 3) The religious and political competitions of the governments of this period [Safavieh] with other governments [Osmani] in order to encourage the people of Iran to visit the shrines. 4) The military and administrative dimension and the political competition of the Western governments such as Russia and England were taking steps to dominate the roads of this region in the advancement of their colonial interests. In the end, what can be said about these ancient ways: that they are the same communication networks of today that have continued to exist with little changes.