Abstract
Ardebil’s Jomeh Mosque is located on an ancient beat that has been the city’s cemetery for centuries. All written sources and archaeological evidence state that the mosque has gathered artistic and architectural innovations from the early Islamic centuries to the Qajar era. Today’s remnants of the building are located in the northeast of Ardabil city and due to measures to preserve the building, it still maintains its firmness. The main purpose of this research is to identify the structural, physical and decorative characteristics of the building in different historical periods. The present study seeks to answer the following questions. What changes have been made to the spatial structure and structure of the mosque from the beginning of its emergence to the contemporary period? And in terms of map and archaeological evidence, which buildings are comparable to the Jomeh mosque? The research method is interpretive- historical and analytical. In addition, documentation and comparative studies have been the basis of the work. The data collection tool is library and field. Based on the results of the research and according to the narratives and writings of researchers and the results of archaeological studies, it can be concluded that its original building dates back to the early Days of Islam, which has been destroyed and rebuilt several times during different periods and has elements of Deilami, Seljuk, Ilkhanid and Qajar architecture and contemporary era. The current persistence of the Jomeh Mosque has Seljuk architecture, but the interior and decorative arrays of the building are in contrast to its façade. In terms of architectural structures, this building has a combination of four arches with porch, which is very similar to seljuk-like, comprehensive and comprehensive buildings of Uremia. Also, the pillar discovered in The Nave have a clear similarity with the historical mosque of Damghan and Jomeh Nain.
Keywords: Ardebil, Friday Mosque, Historical Developments, Analysis of Physical Structure, Building Decoration.

Introduction
Ardebil’s plural mosque is located in the northeast of Ardabil city over an artificial pulse of approximately 5 meters, among the neighborhoods of Pir Shams al-Din and Abdullah Shah. Among the people, it is known as “Jomeh Masjid” and is among the early centuries-old Islamic buildings in Ardabil. Studies have been conducted by domestic and foreign researchers about the emergence and evolution and the manner of the destruction of this cubic building. Today, only the remnants of the dome and porch, which were later reshaped and transformed into an indoor nave, and the minaret remains solitary.
Even some scholars are skeptical about the use of this building as a mosque. In recent decades, archaeological excavations have been carried out in this mosque and have been able to recognize some of the architectural features of this mosque. Considering that this mosque reflects the art and architecture of different periods of the Islamic period in Ardabil and also as one of the few remaining buildings in the primary and historical core of the city, identifying and studying the characteristics of this mosque can help to further understand its architecture, decoration and comparison with its contemning buildings. It has been tried to collect as much information as possible from the characteristics of this mosque through library studies, reporting archaeological excavations and using surveys and visits to the site.
The research questions are as follows: 1) what changes have been made in the structure of the mosque from the beginning of Genesis to the contemporary period? 2) Which decorations belong to which periods? 3) In terms of the physical and decorative Friday of the mosque is comparable to which buildings? The research method is descriptive-analytical and the data collection method is a combination of two methods of field and documentary (including identification, study, classification of information, analysis of them and data collection on the subject of the study).

Materials and Methods
The research method is descriptive-analytical and the data collection method is a combination of two methods of field and documentary (including identification, study, classification of information, analysis of them and data collection on the subject of the study).

Data
Jomeh Mosque, which was once the most elevated building of the city, is formed in the present situation from three parts: 1- dome house 2- Ivan, which is now a mosque and its southern side leads to the dome space through a large mouth and elevation. 3- Minaret located along the middle axis of Seljuk Mosque (Shahbazi Shiran, 2019:9). Considering the present situation of the mosque, it seems that this building is the same mosque that historians of the early centuries have described about it. In some sources, historians have generalized descriptions of the space of the old mosque.
In the early Islamic centuries, a space called a mosque, a large fence around the city with gates on four sides and a crucifix-shaped market that formed these factors formed the main core of the city. Archaeological studies in recent decades (1974, 1988 and 2019) can help. The discovering of northern and western naves with the base of the pillar as well as their similarity with the pillars of early Islamic mosques is consistent with the statements of Islamic historians. Descriptions mentioned in historical texts about the mosque can help effectively within the area of the building. It is also said that in the early centuries, the city had a mosque (Baladi, 1967:167-163). The Safavid travel writers’ report also mentions the Friday of Ardebil Mosque and shows that the building was still functioning in worship before this period despite destruction in some parts and has attracted the attention of tourists (Yousefi, 2020:913). This is a reason for historians and Orientalists who have described and visited this building.

Discussion
Our knowledge of the building in the early centuries is based on historical sources and archaeological reports. The mosque in the Deylamian era had the foundations of thick and polygonal pillar. In the Seljuk period, it was fourfold (Torabi Tabatabai, 1355:284) and a low-rise dome. In the Ilkhanid era, in addition to the construction and restoration of destroyed sections, the thickness of the southern wall has increased (Siro, 1988:184). And tile and gypsum decorations were added to it. From the Qajar era, the foundations of four-sided pillar were obtained (Shahbazi Shiran, 2004:28). Archaeological discoveries have led to the identification of three architectural periods indicating the evolution of architecture from historical period (problems) to Qajar era in this section (Yousefi, 2020:912).
The ancient excavations of Shakhti have shown that contrary to what was thought until then, the Jomeh Mosque was not exclusive to the dome and the remains of the porch, but had several extensions and components and encompassed a wide space. In total, seven pillar stands emerged from the total base of western nave pillar and showed that more remained intact (i.e., 34 and 35). Also, in 1988, the first trench encountered the remains of a huge stone wall stretching west along the outer wall of the southern wall of the dome. The wall itself is built on ancient remains and underneath it are buried pieces of brick inscriptions in the prominent Kufic script.
The construction of northern pillar is based on a kind of reminiscent of the pillars of our pre-Seljuk mosques (3rd and 4th centuries AH) including the historical Damghan Mosque and the Nain Grand Mosque, and these pillar should be considered as pre-Seljuk. The minaret of this building is completely solitary and there is no sign of its connection to the Seljuk building. In terms of the type of plan, it is possible to compare the Jomeh Mosque of Ardebil with the Bersian Mosque and the Grand Mosque of Uremia, which is one of the buildings of the Seljuk era.

Conclusion
In the 4th century AH, Ardabil city was the largest and most important city of Azerbaijan according to historical sources and the center of that state and the headquarters of the army. On the ruins of the primary mosque, one of the primary pillar mosques, which is composed of different courtyards and naves, parts of it have been destroyed and the soil has been destroyed. According to archaeological evidence, the initial mosque had a columned nave map with a map and pattern of early Islamic mosques. Ardebil Mosque in its Seljuk form consists of a dome and a porch in front of it, and the results of the Jomeh mosque survey show the continuation of the application of such proportions before the construction of the Ilkhanid era. According to the map, these mosques are comparable to their contemporary buildings including the Bersih Jomeh and the Jomeh Mosque of Uremia. According to the comparison of the building with the Barsian community, it can be said that by following the usual customs, the Chahartaghi Mosque of Barsian has at least definitely influenced part of the detailed structure, façade and map of the Jomeh Mosque, and the plans of the building (Barsian Mosque) have been expressed completely differently in the work of the next architects (Jomeh Mosque). The other is that Ardebil’s plural mosque is so closely based on the Jomeh Mosque of Uremia that the direct architectural impact of the Jomeh Mosque of Ardebil on it is hardly undeniable.
Considering that the quadrilateral and porch composites are more closed than Fermi’s four-porch plan, therefore it is more proportional to the cold climate of Ardabil region and finally, due to the fact that the body is subject to climate or function and the porch is located in the four-fold plan on the northern jab, it is naturally used in mosques as a cold part. Also, the decorative arrays used in Ardabil’s plural mosque have been used in perfect harmony with the construction periods. Considering the identification of decorative arrays, the Seljuk period to the end of the Qajar era was enumerated for interior and exterior decorations of the mosque.