The Study of Formal Elegance in the Iranian Domed Squares (Ninth to Twelfth Hijra Centuries)

From the aesthetic impression viewpoint, the significance of domed square in Iranian architecture has been noticeable for architects and designers of different eras. The aim of the present study is to recognize the formal, geometrical and proportional features of the Persian domed squares with regard to the visual quality of elegance. For this purpose, the structure, various types and evolution process of domed squares were initially studied. Then, 18 domed buildings were selected among the mausoleums pertaining to the ninth to early twelfth hijra centuries. The geometric characteristics of the elevations of the building were studied using the modeling method and designing geometric analysis tool based on the regular pentagon. The study was limited to general form and the three main parts of the dome, the drum, and the base. The height from the top (dome vertex) to the ground level was assumed to be equal for all buildings. In the second stage, based on the literature review, as well as the analysis of the geometric features, four main indicators were determined to evaluate the physical characteristics in terms of formal elegance, which included the ratio of height to width, the ratio of the dome height to the total height, the ratio of the dome width to the total width and the vertex angle of the dome arch. After determining the indicators, the elevation of each building was studied using them. The results showed that the designs of domed squares pertaining to the era in question consisted of a common framework such that in the most cases the elongation of the dome in height was greater than two parts of the drum and the base, and the upper part (consisted of the dome and the drum) had more than half the total height of the building. Nevertheless, variations were evident, especially in terms of the form and proportions of the upper part in structures of the two periods, such that the elegance of elongation in height amidst the Timurid and early Safavid periods, and the elegance of harmony during the Safavid period has been more emphasized. However, in terms of height and width divisions and the dome vertex angle, there were no major differences between the Timurid and Safavid periods. It can be stated that during the Timurid period, the use of discontinuous double- shell domes became prevalent and architects of the Safavid period continued the same method and created geometric harmonies to adjust the height and move towards square proportions, which is indicative of the desire to create more harmony and balance during this period. Moreover, based on the information obtained from the height to width ratio, the difference between the minimum and maximum values of each sub-indicator is greater in the Timurid era compared to the Safavid era, which suggests a greater diversity in the design of such buildings during the Timurid period. The common geometric pattern and the indicators presented in this paper can be used for the aesthetic assessment of similar domed squares as two complementary methods.