Built on the summit of a hill, this Zoroastrian fire temple (ateshkadeh) is believed to have been built by Ardashir I, the founder of the Sasanian dynasty.

The temple is a simple square pavilion, with a dome carried on four heavy piers joined by arches. The arches were built simply by bridging the piers, without a keystone. Characteristic of Sasanian architecture, this technique is also seen at a larger scale at the Taq-i Kisra. The dome, which only covers the center of the pavilion, is raised on a low, square drum set in from the piers. Four small squinches brace the corners of the drum on the inside. There is a small window on each side of the drum. Rubble stone and plaster were reinforced with reeds grown on the site to construct the pavilion. The dome was constructed of rubble stone and gypsum mortar, with the support of wooden ribs.

Although fire temples, such as the Chahar Qapu at Qasr-i Shirin, were built with living quarters for priests, the temple at Niasar stands alone. Referred to as chahar taq, the domed pavilion typology of the fire temples remained in use during the Islamic period, as exemplified by the garden pavilions (hasht bihisht) of the Safavids.

Sources:

Monneret de Vilard, Ugo. "The Fire Temples." The Bulletin of the American Institute for Persian Art and Archaeology 4 (1936): 175.

Boyce, M. "On the Zoroastrian Temple Cult of Fire." Journal of American Oriental Society 95 (1975): 454.

Yamamoto, Y. "The Zoroastrian Temple Cult of Fire in Archaeology and Literature." Orient 15 (1979):19-17.

Godard, Andre. The Art of Iran, 181-188. New York, Washington: Frederick A. Praeger, 1965.

Herzfeld, Ernst. Iran in the Ancient East, 301. London: Oxford University Press, 1941.

Keall, Edward. J. "Archaeology and the Fire Temple." In Iranian Civilization and Culture (Charles J. Adams, ed), 15-20. Montreal: McGill University, Institute of Islamic Studies, 1972.