Abstract
The city has more than one enclosed enclosure inside the barrow, and it introduces more than one area. Cities have seen profound changes in industrial, social, economic, political, and in particular their demographic, in their relatively long history. The oldest cities between the end of the 4th millennium and the beginning of the third millennium BC They emerged in western Asia and in places where their climate was favorable, and the fertile land suitable for cultivation .Also, the city’s urbanization in Iran dates back to the fourth millennium BC, But the process of city formation and the continuity of urbanization has been gradual in its own way. The Iranian city’s security includes the features and values of the architecture and urbanization of Iran, prior to the arrival of Islam. After the arrival of the Arabs in Iran and the formation of a unified Islamic state in the lands under Islamic domination, the emergence of sprouts The early buds of the new towns, these new towns, originated mostly from Islamic teachings, are divided into two main categories Cities left from civilizations before Islam or cities built by Muslims. The Islamic mayor was structurally persistent in the urbanization of the Sasanian era, and its physical elements were mostly derived from culture. The rich are Islam and represent Islamic civilization and culture. One of these cities is Qazvin, whose core was formed during the Shapur Sassanid dynasty and gradually developed and expanded during the Islamic era, and during Safavid times, Shah Tahmasb was chosen as the second capital of this dynasty.
Keywords: City, Urbanization, Iran, Islam, Qazvin.

Introduction
The word “city” has a long history in Iranian languages. The concept of the city is simply not possible, because civilization begins with urban life, as a result civilization has a direct relationship with urbanization or city. The process of the formation of cities and states for the first time during the third millennium. Based on the evidence available in the Middle East and the regions. The southern and central middle and middle plains of Khuzestan, Nile valley in the north of Aswan, the plains of the Iranian plateau from Fars to South Turkmenistan have been the main centers for the expansion of early cities in the semi-arid lands of Western Asia. One of the major differences between cities yesterday and today is their size, which initially made it difficult to distinguish between the city and the ten because not only the size of the small towns and their population was limited. But the ten and the city, as well as the dominant economic activity, were the same. Each city has different sections that are evidenced by evidence Exploring the ancient sites, the main parts of cities are the structures of the living city, including: temples, palaces, warehouses, defensive walls, houses Residential neighborhoods, workshops and industrial neighborhoods of cities, cities of the dead or cemeteries. In Iran, the process of urbanization and urbanization of the fourth millennium BC It began with the identity of cities and their architecture before the arrival of Islam into Iran But with the arrival of Islam to Iran, we are witnessing the formation of new Islamic cities, and pre-Islamic Pre-Islamic Iranian cities, including Qazvin, are developed and expanded with Islamic elemental elements.

Creation of the First Cities and the Formation of the City of Qazvin
The word root of the city’s name indicates that the city has a semantic meaning over an enclosed enclosure within the barrow, and has more than one district (rural district, district, county, and province). One of the major differences between cities today and tomorrow is their size. At first, it was not easy to identify the city and ten of them. The city and township in Iran has a long history of civilization. And exploring the ancient sites of Iran dates the city and urbanization to the fourth millennium BC. The Iranian identity of the city includes the features and values of the architecture and urbanization of Iran before the arrival of Islam into Iran. Qazvin is one of the cities that was created during Sassanid era and on the orders of Shapur Zoltakht and the original city In the form of a fence and a gable under the name of Shapour’s fence, there were gates in different directions; Qazvin also had a city within the first city under the name of Sharistan or the city, which was later mentioned in the Islamic period by Islamic historians. On the edge of the city and around it there were gardens and fields that Naser Khosrow in the century 5h. q These gardens were mentioned without a fence, and these gardens during the Safavid period and during the Qazvin’s capital created the Gardenshahr of Qazvin, and the works of these gardens still remain in the city until now. During the Safavid period of Qazvin, the name “Dar al-Saltanah” He took himself and chose it as the capital of the king of Tahmasb.

Conclusion
Qazvin is among the cities that has been of special importance in all historical periods, according to written documents written by historians and geographers of Qazvin city by Shapur Zoltakht. It was called “Shadshapur”, but there is however no evidence of the state of the city during the Sassanid era. The only references mentioned in this article are the base and the boundary of Qazvin. In this period it is for the war against the Dalian, which most historians have pointed out. With the arrival of Islam in Iran and the conquest of Qazvin by Muslims, the city gradually expands and the core of the city for its development is the location of the Shapouri fence, which in the texts Historians have been referred to as the Keswin fortress, and in the post-Islamic periods, the city has expanded to this area. On the other hand, the city of Qazvin is located on the east-west and north-south communication highways.

Abstract
Ujan covers about 90 hectare area, where locates 5 Km away from modern Bostan Abad. Earlier construction of the urban center dates to 4-6 AH centuries that coincides to Seljuqs era. It developed during 7 and 8 AH centuries and reached to summit during middle Ilkhanid to Safavid period. It collapsed and destroyed during Qajar period. Here, there is an attempt to study effective elements in formation of Ujan and its consequent function, using descriptive-analytic view and historic research method, based on archaeological-environmental landscape. Finally, it is involved in reasons of collapse of the city. Bibliographic and field studies indicate that construction of the city was for midway positioning. In addition, present paper presents subjects about political and social history, architectural remains, urbanization, cultural remains, and different districts of the city including cemetery and administrative center. 
Keywords: Ujan, Seljuqid, Ilkhanid, Bostan Abad, Urbanization.

Introduction
Different factors involve and play significant role in formation of urban centers. Emergence and development of Iranian cities followed geographical, social, religious, defensive, administrative, and commercial conditions. Commercial routes and passages were effective and affected factors in formation of urbanization. Investigating such factors is effective in responding to location and reasons of emergence of a given city. Road networks were achievement of development during time, whereas dominated by various political, religious, security, and cultural elements. Reasons of abandonment and collapse of urban centers vary according to strategic and geographical position and function that divide to two natural and human factors. Generally, effective natural factors in abandonment of urban centers include earthquake, shift of rivers’ bed, landslide, drought, and lack of natural defensive barriers. Human factors could accelerate abandonment of an urban center that include remoteness from main routes or even side roads, warfare, disease, administrative policy, lack of enclosures and secure defensive ramparts. Cheap and low quality materials are among other factors that cause collapse of a city. Every urban center have especial function that suggests foundation of the area accordingly; among them are mining cities, ports, industrial cities, administrative-political cities, tourism cities, and etcetera. Understanding factors and elements of formation and development of cities are among the most important discussions since earlier times that attracted scholarships and resulted to different theories and models to analyze urbanization.   

Features of cities during Islamic period
Among features of Islamic urban centers were economic, social, military, and especially religious developments that played effective roles in formation and developments of urban centers even in earlier times. Islamic urbanization related to stability of government too, whereas emergence, development, and collapse of a city related to political circumstances. General studies on maps of Islamic cities indicate that many cities followed similar method and style of urbanization that shows probable common designer and architecture. Scholars also believe that designers and architectures planed maps before construction of buildings and constructed buildings and structures accordingly. In a miniature painting, dated to Babur reign, he points to a map in the hand of a man that designed it (Kiani 1365: 205). Islamic architectural thought in Islamic countries characteristically comprehended principles and generalities of civil programs then involved in details (Othman 1376: 27). In planning cities, there was emphasis on Jami and administrative buildings, where located public buildings in city center for public access. Tendency to privacy and peace in residential areas caused Iranian Islamic cities divide to two public and private parts, similar to pre Islamic urbanization. Bazar complex and extensions was pulses of urban life, where presented public and social activities. Residential area was private part of the city, where rest and peace dominated living atmosphere (Kheir Abadi 1376: 44). One can study urbanization according to different point of view. Scholar such as economists, politicians, historians, geographers, and philosophers investigate the subject from their point of view. There is not certain answer to relations between Islamic view and urbanization and their mutual effect. There are variations in effects on urban spaces and structural characteristics. According to Stern, urban life style followed earlier criteria after Islamic conquests, and it became Islamic in forms and generalities (Razavi 1387: 105-112). Cities are the most genuine center of civilization and cultural treasures, what should be recognized to make possibility to investigate evolutionary history of human life. Therefore, investigating cities that remained from earlier times play significant role in understanding political, social, administrative, economic, and cultural structures of societies that created them (Karimian 1384: 111-121).  Papoli Yazdi, quoting from Hufer, says that city is relation among six aspects: economic structure (variation of activity), social structure (social classes), body structure (public buildings), geographical position, law position, and political life (Papoli Yazdi and Rajabi Sanajerdi 1387: 50).

Ujan, Formation, Flourish and Collapse According to Historic Sources
According to historic sources, Ujan was alive earlier than Ilkhanid period, especially during Seljuq era. It existed as a strategic and important urban center, following different events including earthquakes, and wars; it was only during Ilkhanid period that the city reached to summit and glory. Every given historic city or monument partially imply political, religious, and social conditions that consequently followed political evolution, therefore, emergence cities with architectural nature is among the most important social evolution of Ilkhanid period. Historic city of Ujan was among important Ilkhanid cities (summer residence) at south of modern Bostan Abad, eastern Azerbaijan, where reconstructed during Ghazan reign. Ujan is among the cities that constructed by Ilkhanid rulers, while their Iranian viziers Islamicated new urban centers. Endowed city of Ujan was the summit of flourish in construction of public, martial, and administrative structures, and throne of Ilkhanid princes. 

Investigating Formation, Development and Collapse of Ujan, According to Archaeological Findings
Recognizing location of Ujan was at 1392, according to archaeological surveys at Bostan Abad regions. Historic and geographical descriptions of Ujan, especially Metraghchi’s illustrations remarkably helped to recognize location of the lost city. Site of Qullar, Ashraf Abad village (part of ancient Ujan), at eastern Bank of Ujan Chai River locates at 46-49-25 latitude and 37-35-48 longitude, and 1787 m longitude. Site of Dali Dareh Si locates 1 km away from Qullar (fig. 3). Constructing railway divided the area to two parts, and irrecoverably damaged the site (Velaiati 1385, 1392).  

Conclusion
Urban centers at the routes of main commercial and connecting networks, while potentially interconnected to other major cities or cities that geographically have abundant water sources, have opportunities to develop and survive. Therefore, location of city at commercial roads was highly signified, because made them capable to meet their needs and export their surplus. Urbanization at main roads highly signified and caused to flourish and wealth. By the circumstances, old cities appropriately coped with commercial activities and caused to raise townships and commercial parks next to carvansarai and small residences at ways. Alternatively, new urban centers emerged; among them was Ujan as an important city during Islamic Middle Ages at northwestern Iran, Azerbijan. 

Abstract
One of the facts that can be seen in the archaeological contexts of the late Bronze Age in the abandonment or excessive reduction of the enclosures. At the end of the Bronze Age, many sites and settlements in the Iranian Plateau and outside the Iranian Plateau collapsed suddenly and unexpectedly, or the growing process of these societies has stopped. Researchers have considered several factor such as floods, earthquakes, immigration of newly arrived ethnic groups, etc. for this event, to these factors we can also add the effect of factors such as over urbanization, which has not been addressed much. As a result of over urbanization, challenges such as; Regional thermal changes, destruction of habitat and biodiversity and ecosystem as accelerating factors in the crises of this period could further worsen the situation. The result of this research show that after the increase in population in urban centers due to the lack of administrative planning to control the conditions caused by dense urbanization and as a result the disruption on environmental order and natural balance, the society has tried to restore the natural conditions as a stable system this attempt to return to the balance has been manifested in various ways, such as the decision to leave large settlements and move to peripheral and peripheral areas with sufficient food and water resources. The evidence of this event can be seen in areas such as Merv, Northern and Southern Balkh, and Doab areas in eastern Sind; in some cases, the crisis in the societies has increased and it has appeared in the form of newer problems such as famine and epidemics, inter regional conflicts and such things, which have led to the collapse of societies.
Keywords: Bronze Age crisis, Late Bronze, Over Urbanization, Eastern Iran, The Decline of Settlements and Civilization. 

Introduction
Over urbanization or excessive urbanization is generally used in cases where the urban population has grown unplanned and beyond the capacity of the environment and city administration, which causes the transformation and sometimes degeneration of urban communities (see Sovani, 1964). Therefore, the increase in the number of the population and the lack of environmental resources in the administration and organization of the urban population could act as a factor to disrupt the path of the Bronze Age societies. The decline of settlements and civilizations at the end of the Bronze Age is very important, and the first major collapses of the prehistoric era took place at this time, which occurred widely and in large areas of the old land. The Bronze Age in the archaeological literature refers to a period when societies gradually more from rural to more complex or urban and create trans-regional connections. Obviously, what is expected is the continuation of the development and progress of societies towards the emergence of larger and more complex civilization and states, which reached their peak of prosperity during the middle Bronze Age (see Tosi, 1976: 168). But what happened in the late Bronze Age is the abandonment of sites and depopulation of a large number of them, which can be seen as a chronological break in many Ancient sites? The evidence indicates an event during which large settlements such as Shahr-I Sokhta (Tosi, 1968). Mohenjodaro (Wheeler, 1968), Harappa (Wheeler, 1968), Altin Tepe (Masson, 1981), collapsed, although some small settlements such as Tekem Tepe (Kohl, 1984) continued to exist without any interruption. The concentration of population in urban areas and the impossibility of providing in frastructure needs in urban life due to the occurrence of over urbanization had led to disorder in social structures and population decline in Mohenjodaro and Harappa settlements. If the elites of the society do not manage or solve the problems caused by excessive urbanization, difficult conditions will arise and the society will probably solve the problem or become a problem in the form of a self-organizing system. The evidence shows that in some settlements such as Mohenjodaro, Harappa and Altin Tepe, people decided to leave the large settlements and settled in peripheral areas, and this caused the settlements to become uninhabited in the late Bronze Age. 

Identified Traces
Urbanization, which was actually a cultural and social revolution, appeared sometime between the end of the fourth millennium and the beginning of the third millennium bc in western Asia, Egypt and Mesopotamia (Childe, 2019:1). But at the end of the Bronze Age in a wide area of the east, especially the southeast region of Iran and even beyond the current borders of Iran, such as; Central Asia and the Indus valley, many large settlements such as Shahr-I Sokhta (Tosi, 1968), Tepe Hesar (Schmidt, 1937; Dyson, 1989), Namazga (Kohl, 1981) area have declined and shrunk excessively. There are several theories about the crisis of the late Bronze Age, such as the invasion of the Aryan tribes (Girshman, 1954), disease (Robbins Schug et al., 2013), famine and earthquakes (Nur, 2009), etc., but since this discussion is about societies with an advanced level of technology and in constant relations with are their peripheral areas. The factor of excessive urbanization can be added to the above. Rapid urban growth will have consequences for the urban society. Such as the lack and absence of drinking water, urban heat island effects, unpredictable rainfalls, and increasing demand due to population growth cause environ mental destruction and air pollution. For example, in the Indus valley in period IIIC, due to extra-regional trade and large inward migrations, the previous organized settlement pattern was disrupted. The houses in the main areas of the city were thrown into the streets and then at the end of the Harappan phase, the population density decreased and some of them were concentrated in the main areas of the city and the other part moved to the east. In Turkmenistan, even though the archaeological data indicates a decrease in the Kopedagh area, no settlements are abandoned in Atak and other areas, especially Merv and Balkh.

Conclusion
In general, based on archaeological findings, the cities were formed from the old Bronze Age and reached their peak of prosperity during the middle Bronze Age. But at the end of the third millennium and the beginning of the second millennium B.C. the evidence indicates that the sites were excessively shrunk and empty of inhabitants, or the collapse of large settlements. This could have been caused by over urbanization on the basis that whenever the society’s population grows beyond the environmental resources and facilities necessary to organize people, it can create crises for urban societies. Crises such as; the increase in urban rainfall and temperature, the increase in urban waste, the lack of drinking water sources and the destruction of the environment for human well-being in large societies with high population. With the increase of urban population and the lack of resources to organize people it leads to an increase in crime, marginalization and disorder in urban organization, and when the political rulers cannot solve or manage the created problems, the people of the society left the cities and went to the marginal and peripheral areas with stable food and water resources, such as Merv, Northern and Southern Balkh, to continue their lives.