Using domes to cover large gaps has a long history in Iran. Lack of solid and long woods, which indeed are the main elements of the flat coverage, has introduced vaults and domes as the popular options for coverage purposes. In Iranian architecture, domes enjoy a considerable position. The Iranian Muslim architect has used his talent and taste, as best as possible, to build mosques, as not only structural considerations have been considered in his works, but also the aesthetic aspects of domes have been dealt with.

This study tries to analyze the gradual evolution of mosques' domes during different historical epochs by emphasizing the dimensional proportions of domes, as an aesthetic component. It also answers the question that is there any significant relationship between aesthetic components of domes during different historical eras and in a single geographical area? For this purpose, initially the available related literature was reviewed to compile typology styles and to elicit effective components in order to compare and classify domes. Limiting these studies to the Central Iranian Plateau helped us to control our study's range. Methods and documents used in this study were sections of domes of mosques and the mentioned geography regarding the bibliographical references. Achievements of this study were organized using descriptive-analytical methods, depicting scatter diagrams and analysis of statistical data. This study showed that the external deflection of mosques' dome has been increased by Mozzaffari-Teymurid, whereas it started to decrease during Safavid era. Unlike the external deflection, the internal proportions in mono-shell and double-shell domes had overlap with each other and there are not very different. At the same, the historical evolution of form of Iranian mosques' domes follows Khagi, Nar and shamrock domes.