In the early 21st century, during an excavating of a village on Farahan plain, some remains of an important monument including part of a large brick column and several walls were discovered. For a decade, despite national registration, no scientific and comprehensive study was performed on these remains until the time when the remains captured the attention of the authors of this paper during their archaeological study of the Farahan plain. Therefore, considering two main objectives, the chronology of the discovered pieces and determining their real identity, initially, a comprehensive archaeological survey was carried out on the Fardaghan region and samples were collected from different areas of this plain; afterwards, the cultural data were typologically compared. At the next stage, historical evidence was sought in written sources using a historical approach in order to determine the identity of the site. The results indicate that the current building belonged to the Sassanid period that has been also used during the Islamic era after a functional change. It is highly probable that this building is the one mentioned in some written sources such as Ibn Yaghoubi’s Mokhtaser Alboldan. In early Islamic centuries, this fire temple was changed into a fortified castle.
