“At the end of Shahrivar (the sixth month of the Iranian calendar, August 23-September 22) we can determine exactly the day of the month by the light shed by the sun on Zoroaster’s Kaba. It has been used for daily needs, determining the time of cultivating crops, and collecting taxes,” Reza Moradi Ghiasabadi explained.

Zoroaster’s Kaba is located beside the Achaemenid dynastic era Naqsh-e Rustam monument, just a few kilometers from Persepolis in Fars Province. The inner room of Zoroaster’s Kaba is 2.5 x 2.5 meters in area.

“To realize the fact that the building had not been a center for storing governmental documents and books only requires that you enter the monument. You will grasp that such a small building could not be used as a center for documents of a great empire like the Achaemenid dynasty,” Moradi explained.

“Some foreign astronomers recently visited and photographed the monument and they are currently studying it due to my theory,” he said.

“Iranian cultural officials pay no heed to the new theories posed by Iranian researchers. For example, if it’s said that the statue of Shapur I has been discovered at Bistun, they will go there to see the artifact, asking for no proof of its accuracy, but my or my colleagues’ research, which has no visual evidence, is not considered,” he complained.

There are various theories on the original purpose of Zoroaster’s Kaba. Some experts believe that the monument was the home of a complete copy of the Avesta which had been written on 12,000 cows’ skins. Some Orientalists also believe that Zoroaster’s Kaba was a place where the Zoroastrians’ sacred fire was kept burning eternally.

A number of other researchers say that the monument is the tomb of Smerdis, the son of Cyrus the Great, who according to Greek sources was murdered by his brother Cambyses (530–522 BCE).

Zoroaster’s Kaba bears a Sassanid era inscription explaining the historical events during the reign of the Sasanid Emperor Shapur I (241-272 CE).

The trilingual inscription, written in the Sassanid and Parthian dialects of Middle Persian and ancient Greek, describes the war between Persia and Rome in which Shapur I defeated the Roman emperor Valerian, who was captured in June 260 and died in captivity.

European scholars have named the inscription “Res Gelase Divi Saporis” (The Book of Deeds of the Emperor Shapur).