Buildings with religious functions were among the extant buildings of Ancient times. Among the buildings having existed since ancient history in Iran and which were regarded by Iranians as places for worship and rituals, one could refer to fire temples, idol-temples and monasteries, (synagogue and convents). Unlike the aforementioned buildings, Catacombs in ancient times were places for burying the dead. Thus, like the aforementioned buildings, they had religious functions. Many writers of works belonging to Islamic era paid attention to many of these buildings. All of the authors admitted the existence of such buildings and their religious functions although the Islamic authors did not have profound knowledge about these archeological buildings and their descriptions and reports about such buildings were intermingled with legend. The present paper is an attempt to examine the religious functions of these buildings and search in descriptions and reports of Islamic authors with a descriptive-analytic approach. The assumption of this research is based on the fact that and the collection of reports from the historical texts of the Islamic period is very brief, and because of the time gap between the era of building prosperity and the time of recording and recording them in these monuments, it is scattered and somewhat legendary. The result of this research suggests that in the descriptions of most Islamic historians, the principle of the existence of these fire temples and their religious function is confirmed by the relative domination of Islam. But in part, the prosperity and the existence of the conquerors and the conversion of the peoples of the prominent countries into Islam have prevented the display of a clear image of these works.