A New Research on the Architectural Structure of Mosque-Castle of Jokhah-e Tabas

Abstract
In the architectural history of the Islamic period, the mosque, owing to its religious character, has been regarded as a key factor in the formation and expansion of cities and villages. The Jokhah Old Mosque, located in the village of Jokhah near Tabas, is a significant architectural monument of the Islamic period. Although the Cultural Heritage Organization has conducted limited studies to record, date, and describe the building, no coherent investigation of its design, structure, and chronology has yet been undertaken. Since no mention of this mosque appears in any known source or text of the Islamic period, the present research examines the formal, spatial, and technological characteristics of its architectural structure to identify and interpret the building. Drawing upon field surveys, analysis of the physical elements, and comparison with analogous examples, this study aims to introduce the mosque’s spatial organization, establish its historical phasing, and physically analyse its formal and spatial elements. The research method is descriptive-analytical. The approach involves field investigation and direct observation of the mosque. The comparative dimension of the study is based on library sources, and through interpretation of the findings, the architectural characteristics and design principles employed in the building are identified. During the research process, the design features and spatial configuration were compared with those of other mosques of the middle Islamic period to qualitatively assess similarities, changes, and transformations in the spatial structure. The findings indicate that the building was originally constructed with two porches during the middle Islamic centuries, and a third porch was added in a later period, leading to alterations in the plan layout and the arrangement of its spaces.
Keywords: Mosque-Castle, Architectural Structure, Dating, Islamic Period, Jokhah-e Tabas.
 
Introduction
In the architectural history of the Islamic period, the mosque, as a building type, has been one of the key factors in the formation and expansion of cities and villages, owing to its religious function; it is regarded as the most important Islamic building, serving as a place of prayer and other acts of worship. Moreover, mosques in each Islamic period and across different climates exhibit distinct architectural styles and patterns; therefore, the study of mosques, among other Islamic building types, is of great significance.
According to the findings of the 2015 archaeological survey, the village now known as Jokhah (formerly Chardeh) contains two mosques. The name Jokhah was applied to this village in the contemporary period, before which it was known as Chardeh. The New Mosque, according to its dedication inscription, was built in the Qajar period within the fabric of the new village of Jokhah. The Old Mosque, known as the Castle Mosque, is located outside the present-day village and is the subject of this research. This name derives from its proximity to the old, large castle of the village. Unfortunately, no information regarding the mosques of Jokhah village has been found in any Islamic source, text, or even in the travelogues of the Qajar period. It appears that the location of Jokhah village on the route connecting Tabas with the central regions of Iran increased its importance and led to the appearance of several significant Islamic buildings, including the Old Mosque. The irregular plan and the distinctive three-īwān plan of this building are the main reasons for undertaking this research. The architectural style and characteristics of the building bring it close to the middle Islamic period; consequently, the purpose of this research is to carry out a comprehensive study of the building, to achieve an understanding of its physical identity, to trace the evolution of the design, form, and function of its architectural spaces, and, finally, to date the structure. Information about the Jokhah region is very scarce. Apart from a brief description and dating of the building carried out by the provincial Cultural Heritage Organization, no serious or detailed study has been undertaken in the field of recognition and analysis of the architectural structure of this historical building. Accordingly, this research is fundamental in type, and its method and nature are historical.
 
Discussion
The building is positioned along a northeast–southwest axis, in accordance with the qibla direction. Qala Mosque consists of spaces such as entrances, a courtyard in the middle of the building, a portico on the west side, two high porches facing each other on the north and south sides, a wide porch on the east side of the building, a nave, and side chambers. Based on the overall design and building elements—such as the use of two porches facing each other, the depth of the qibla porch, and the portico around the courtyard—the location of the main entrance is on the northwest side; this entrance features massive walls that project from the building’s surface and a corridor-like space. The geometry of the courtyard is rectangular, and it is enclosed on three sides. The middle porch on the north side of the mosque, at its rear support, shares a wall with the entrance of the building. In the porticoed mosques of Khorasan, the most important porch, which is situated in the middle of the south side, was intended for the orientation of the building towards the qibla. In the investigation of the mosque, it was found that the two porches on the north and south are not exactly aligned with a common axis, and the south porch is deeper. It is likely that the spaces on the sides of the south porch were designed as naves, although their size and design differ from those of the naves found in two-īwān mosques. Based on the rubble of the long walls left in the middle of the eastern side of the mosque, it is possible that another porch existed in this part of the building, with dimensions that were larger than those of the south porch.
 
Conclusion
Analysis of the findings reveals that certain features of the architectural structure—such as the location of the mosque on raised ground and the construction of massive pillars in the shabestānī space—render it comparable to mosques of the Seljuk period. On the one hand, the use of low-quality materials and the design of two porches are characteristic of Khwārazmshāhī mosques in Khorasan; on the other hand, the heightened and elongated entrance, the addition of a vestibule, and the arrangement of the porch and its side porches are reminiscent of features typical of Ilkhanid-period mosques. Based on the examination of the mosque’s structural and physical characteristics—including its design, architectural elements and components, and its classification as a two-porch mosque—it is possible to place this building among the Khwārazmshāhī mosques of the Khorasani style. The surviving architectural remains attest to the grandeur and significance of the building during its initial construction period. The extension of the eastern porch, the presence of two chapel spaces and a pulpit, multi-layer cladding, restoration work, and the use of pottery in the building’s wall further indicate that the mosque continued to be used over several periods.