Qalat Islamabad: A Newly Built Construction from the Sassanid Period in Fahraj county-Kerman Province

Qalat Islamabad building is located in Fahraj city, at the eastern end of Kerman province, on the outskirts of southern Lut Desert, in the coordinates of 47.480 ° 28 'north latitude, 7.008 ° 59' east longitude and 550 m above sea level. The region has a hot and dry climate, irregular and low rainfall, severe temperature differences day and night and sandstorms. Fahraj is adjacent to Sistan and Baluchestan and South Khorasan. Historical geographical texts of the early and middle Islamic centuries have repeatedly mentioned Fahraj among habitable cities on the edge of the desert. Qalat Islamabad monument was identified during archeological studies of Bam cultural landscape in 2013. In the present study, which was conducted in field and library methods, the architecture of the building was studied. One of the objectives of this study was to determine the use and the possible date of building construction.

The method of research in this paper is descriptive-analytical and data collection has been established by conducting a field survey and studying written documents.

This building is located on a hill with a height of 3.60 m above ground level. The general plan is square with the dimensions of 17 × 17 meters. The main components of this building are a room in the center, twin porches on the west and east sides, a single porch on the north side, an entrance on the south side, four spaces in the four corners of the building and a perimeter corridor. This building has some deviations from the north axis and is slightly inclined to the west. The central room is square with dimensions of 4.70 × 4.70 m. The cover of this space has completely collapsed and no information about it is available. On the east and west sides of the central room, two arches are built symmetrically. The depth of these arches is 40 cm, the width of the arches is 130 cm and the existing height is 1.5 m. On the north side of the central room, an arch similar to the other two sides has been built, with the difference that there is a door in one corner that leads to the north porch. All the spaces around the central room have access to the central room through doorways. The main entrance is on the south side, which leads to the central room. The width of this entrance is 172 cm on the exterior and 156 cm at the end and entrance to the central room. Most of the cover of this entrance gate has collapsed and there are few traces of its entrance. On both sides of the entrance, two pairs of arches are symmetrically installed on the south side. The map of this part of the building is reminiscent of the entrance porch of Firoozabad Palace. However, it varies in dimension and size. There is a porch in the middle of the exterior of the north side. The width of this porch is 1.72 m and its depth is at least 2.18 m. There is a doorway in the end corner of this porch that leads to the central room. The roof of this porch has completely collapsed. The twin porches are one of the most prominent parts of the building. These porches are built symmetrically on the east and west sides. The width of the opening of each porch is 2.40 m and its depth is nearly 2 m. The current height of the porches is 2.5 m. The only remaining coverings of the building are on the west porches and a little on the east side. The coverage of each porch is covered with an arch in the shape of a Oval(Shaljami). At the end of each porch, there is a door that leads to the central room and is located symmetrically on both sides of the arches on the east and west sides of the central room. The cover of these doorways is triangular and made of large bricks. Parts of a corridor can be observed on the east side of the building, and the width of this atrium is 90 cm. Parts of the outer wall of the corridor with a length of 6.80 m and a height of 2.30 m are still standing. This wall is built along the eastern side of the building. The scattered remnants of this corridor on other sides indicate that a vestibule probably surrounded the building. The materials used in the construction of the building are the clay.The dimensions of the bricks used in the construction of the building are 40 cm and its thickness is 10 to 9 cm. The dimensions of the bricks in the triangular cover of the gates are 43 to 45 cm. The northeast corner is a room with a rectangular plan and dimensions of approximately 2.5 m. The northwest corner appears to be symmetrical to the northeast corner; however, the position of the south corner corners is not clear. In the right corner of each space, there is a door that leads to the central room. Some instances of it can be observed in the facades of Sarvestan and Firoozabad palaces, in Sassanid works left from Kuh-e Khwaja and the largest example of it can be observed in the Oval (Shaljami) arch of Taq-e Kasra.

The plan of the Islamabad building is comparable to that of buildings such as; Rahimabad pavilion located a short distance from Qalat in Islamabad, Vandadeh fire temple in Meymeh of Isfahan and Chahartaghi north of Ardakan in Yazd from the Sassanid period. The plan of this rectangular building is the center of the central dome building with four equal porches in four main directions and perpendicular to the central space with a slight difference has a similar structure to Qalat Islamabad. In addition, the central pavilion of the  Lashkari bazaar in Ghazni has a similar plan. This building belongs to the Ghaznavid period and the fourth century AH. The general plan of the Islamabad building is also comparable to the map of some palaces and residences of the nobility of the third to fifth centuries AH in Marv city. The building of Islamabad may be the remains of a palace from the Sassanid period. However, what makes this use questionable is the possible corridor around the building. The rest of the corridor stretches along the east side in front of the twin porches. The corridor is one of the features of the religious architecture of the Sassanid period. Although it may have been just one way. Furthermore, the corridor can be seen in works such as the fire temple of Kuh-e Khwaja with late Parthian and early Sassanid history. Kuh-e Khwaja Fire Temple, Tal-e Jangi and Konar Siah are some examples of fire temples with corridors from the Sassanid period. Qalat Islamabad building with its central square space, porches with Oval(Shaljami) arches in the east and west directions and entrance with Ahang arch in the south and asymmetrical porch in the north looks like a pavilion in terms of function. It is comparable to some palaces and fire temples of the Sassanid period and the early Islamic centuries. Besides, based on the evidence on the east side, the existence of a corridor around the building makes the existence of a religious building possible. Existing porches with Ahang and Oval(Shaljami) arches, symmetry, materials used and pottery findings can be presented from the late Parthian to late Sassanid period and early Islamic period to dating the Qalat building in Islamabad.