Analysis of Prehistoric Architecture in the Northeast of the Iranian Plateau: A Study of Architectural Developments in the Residential-ritual Sections of Damghan’s Tepe Hissar

Tape Hissar in Damghan is an important site with architectural remains of residential-ritual parts belonging to Chalcolithic and Bronze Age (4500-1500 BC), which has been excavated with detailed maps by Schmidt (1937) and Dyson (1989) and others. The purpose of this study is to analyze the architecture of this site in different layers and the main questions are about identifying similar and distinctive features of architectural remains in relation to other findings affected by different cultural changes. The research method is monograph and begins with the analysis of texts and maps based on library studies and is completed by collecting and analyzing the artifacts left on the ground, especially layer IIIB. According to excavations, in the second half of the fourth millennium BC, Hissar was an important site for stone processing and production of copper. Hissar I pottery was also influenced from the west, and Hissar II from the northeast of Iran. The architecture of Hissar has changed along with cultural changes. Materials such as molded clay is used instead of Chine (periods II and III). Details such as the buttress is one of the most important structural features of the II period, which is changed into tower in Hissar III. During this period, decorative niches appeared for ritual or ceremonial buildings. The activity of each room, especially the burned building of IIIB, is separated. In the spatial organization of each house in Hissar II and III, there is a large room (about 4 by 5 meters) with a square heart in the middle, which has a right-angled geometry protected by buttress, and is linked with fire-related activities and perhaps metalworking. It is noteworthy that the general orientation of buildings in different layers remains constant in the form of northwest-southeast, which seems to correspond to the direction of the prevailing winds in the region.
Keywords: Tepe Hissar, Residential-Ritual Part, Plan Analysis, Building Elements and Parts, Evolution of Geometry.
Introduction
A study of the architecture of prehistoric houses in Iran, the evidences of which can be traced back to the seventh millennium BC. Is the first step in recognizing the roots and the formation of the built space in our country. The aim of this study is to investigate the important features of the development of prehistoric architecture in the north-east of the Iranian Plateau in Tepe Hissar. The settlement here starts from the fifth millennium B.C. and continues until the end of the Hissar III, at the end of the Copper Age or Bronze Age, i.e. the first half of the second millennium B.C. According to excavations of Eric Schmidt published in 1937, Tepe Hissar has been influenced by its eastern and western cultures in different periods. As cited by Tosi ,1989, by the second half of the 4th millennium BCE, Hissar had become a major processing site for semi-precious stones and a production site for copper and other metals. The architectural remains of Tepe Hissar are also important and well documented because they are excavated in readable area, in the form of at least three to several neighboring houses, and in the archeological reports of Schmidt, 1937 and Dyson, 1989 they are well documented in different layers. From the third layer of Tepe Hissar (3000-2000 BC), there are remains on the ground, which Dyson considers it as Iran’s most important visible remains from the Bronze Age.
The architectural features that were analyzed in this study are the evolution of materials, geometry change, separation of building parts, complexity of details and decorations, differences in spatial organization of each residential unit and changes in neighborhood texture. In order to find the answers to research’s questions, first-hand library sources, reports of archaeologists’ excavations of the site and scientific-research articles related to Hissar have been discussed. Every information from excavation reports has been distinguished with the help of pattern coding on re-drawn maps. The remains of Hissar II and III, especially the burnt building of layer IIIB have been surveyed on-site in detail in 1994 and 2018.
 
Identified Traces
1. Materials: In Hissar I, oval mud bricks changes into rectangular ones, but Cheene (hand-formed clay) is one of the main masonries. The most common wall material is rectangular mud brick in Hissar III. The burned building is specifically made of molded clay with similar size. The buttress is the most important element to strengthen the walls, which is regulated in the Burned Building of Hissar III in comparison to the shapeless buttresses of Hissar I. The buttress has the form of a solid rectangular square tower at the end of the shorter walls, or perpendicular to longer walls.
2. Details and decorations: most of decoration can be seen in the Burned Building of Hissar IIIB in the form of recessed niches with female figure form. This building has the function of a temple or a house of an important family. One of the main rooms of the IIIB layer has also recessed arched shape niche.
3. Building sections: Large rooms of Hissar II and III have a specific function with central heart. The Burned Building of layer IIIB has sections such as entrance vestibule, store room (of wheat), kitchen, yard, main room with central heart, storage, toilet and tower.
4. Functional separation: Ritual or governmental zoning of burned building separated from residential fabric indicates a move from rural to urban areas.
5. Spatial organization and geometry: The presence of the heart and central fire has caused the importance and added value to the space, which has affected the geometry of the space in the form of the perpendicular walls which can be seen in a large room of layer II and especially layer III.
6. Adjacencies and orientation: The general orientation of all three layers of Tepe Hissar is northwest-southeast, which is derived from climate adaptation, which means the best use of sunlight and overcoming the prevailing winds in Damghan region with this direction northwest-south, south-east. In Hissar IB presence of alleys shows enhancement of adjacencies.
 
Conclusion
The architectural evolution of Tepe Hissar can be interpreted similar to the changes in objects or other archeological findings, which were influenced by external cultures from the east and west of Iran. The second layer of Hissar I, when the potter’s wheel and animal motifs of the potteries (especially goats), entered this area from western Iran, adjacent rooms around the open space of Hissar I has changed into three or more rooms adjacent to alleys and public access routes. The grey pottery entered from the east and northeast of Iran to Hissar II and the changes in the burial traditions occurred.  Along with the flourishing of copper objects, every excavated house has a distinctive room with span on around 4 meters, supported with buttresses and perpendicular geometry. Hissar IIIB is a flourished period with manufacturing of copper and trade of objects, and the Burned Building shows advanced building divisions, structure, decorations and neighborhood.  In the Hissar IIIC, some objects, such as stone vessels, indicate a connection with Mesopotamia, but the architectural remains show similar features as Hissar IIIB.