Adur Gushnasp was the name of a Zoroastriansacred fire of the highest grade, which served as one of the three most sacred fires of pre-Islamic Iran; the two others being the Adur Farnbag and Adur Burzen-mihr. Out of the three, Adur Gushnasp is the only fire that has been discovered and "for which archaeological, sigillographical, and textual evidence are all available." It was based at the modern-day site of Takht-e Soleyman in the West Azerbaijan Province and established in a temple structure constructed by the Sasanian kings. It served as a prominent site of pilgrimage. The name Takht-e Soleyman was first used in the Islamic era; beforehand the site had been known as Mount Asnavand, a name given by Medianpriests. The identification of the site of Takht-e Soleyman with that of the fire temple of Adur Gushnasp became clear when a Sasanian era-bullae was discovered there, which had the following engraving "High-priest of the house of the fire of Gushnasp". The fire is not mentioned in early Sasanian sources, and archaeology suggests that the fire was first taken to the site in Azerbaijan in the late 4th or early 5th-century. Under the Sasanians, the fire was linked with the warrior class, which the Sasanian dynasty itself belonged to. In the same fashion as the Arsacids on Adur Burzen-mihr, the Sasanian kings bestowed gifts on the temple of Adur Gushnasp, the first recorded king being Bahram V. The latter is mentioned in several instances related to the fire, such as celebrating Nowruz and Sadeh there, and also entrusting the high priest to convert his Indian wife. Khosrow I reportedly visited the fire before launching a military expedition. He also bestowed the fire an extensive amount of riches part of the tribute which the Byzantinespaid the Sasanians. Kings were not the only ones who made offerings to the fire; according to the Saddar Bundahesh, it is recommended that when praying to reclaim eyesight to swear, "I shall make an eye of gold and send it to Adur Gushnasp" or, in order to make a child become astute and sensible, send a present to the fire. The fire temple of Adur Gushnasp was renowned for its immense amount of wealth in Byzantine and Islamic sources. The fire temple was sacked in 623/4 by Heraclius during the Byzantine–Sasanian War of 602–628. The Iranians succeeded in saving the fire, which they later restored to the temple, which was quickly rebuilt. The apocalyptical Middle Persian text Zand-i Wahman yasn may report some form of contemporary memory of the destruction of the temple; "They will remove Adur Gushnasp from its place... on account of these armies, Adur Gushnasp will be carried to Padishkhwargar." The fire continued to burn for a long period in the Islamic era, but persecution eventually increased, and by the late 10th-century, or early 11th-century, the fire had most likely been quenched.
