Analytic Study of Mosques Architecture in “Shabistani” and“FourIwan” Styles(Case Study: the Great Mosque of Isfahan)

At the early of eleventh century AD several mosques appeared with a newfound pattern of architectural design in Central Iran, which is known as the symbol of mosque architecture. The specific feature of the new pattern was a high Iwan in each side of the Sahn (mosque yard). So the plan is composed of four Iwans and was named “Four-Iwan” (or Chahar Iwani) pattern. Very soon so many mosques were designed and constructed by using this pattern, so a new style was stabilized and became pervasive. Iranian architects derived popular “Iwan” from pre-Islamic Persian architecture and coordinated it with new religious conditions and finally could find the Iranian style of designing mosques. In Islamic period, mosques were the most significant facility and function in the body of Iran`s cities. So studying architecture of mosques is one of the main keys to survey architecture history of Iran in middle ages. And also it can lead to a better knowledge of social situations and cultural features of Iran`s art. Regardless of roots in basing and reasons of prevalence, collation of four-iwan pattern with the previous one called “Shabistani” and study of improvement of different aspect of architectural design of mosques in Iran is to be investigated in this essay. Architectural differences between the patterns is to be studied. The main criterion to collate the two patterns is Spatial Quality. A sufficient method is needed to find out which pattern is more coherent in quality of space. There are several theories and scientific methods to analyze quality of architectural space, such as “FASA” (Fuzzy Architectural Spatial Analysis) and “VGA”( Visibility Graph Analysis). Because of clear analysis and containing graphical drawings, an architectural theory named “Space Syntax” is considered to compare the quality of architectural space of mosques in each pattern. And also architectural functions and Visual features as two significant criterion in architectural design are compared to conclude the preponderant pattern in designing mosques. At first, function of mosque (saying prayers) and the basic requirements is studied, and then the way two patterns answer the needs is considered in functional comparison. To collate patterns in visual points, perceptual techniques in each pattern is studied. As a case study, the great mosque of Isfahan is analyzed which was early erected with Shabistan pattern in 8 cent. AD and then gradually transmuted into Four-Iwan pattern till 11 cent. AD. The research method Analytic- Descriptive is mentioned to reach a clear comparison of the two pattern. In this method quantities in mosques are analyzed and qualities are descriptive. So the two patterns are totally compared. As the result, to design mosques Four-Iwani pattern sounds to be more preferable than Shabistani pattern. Because it provides a higher quality for architectural spaces. Hierarchy and spatial relations are planned more creatively. And also this pattern helps the plan to have a premier service in the function of mosques: (saying prayers). And eventually ameliorates the “Form” with better sky-lines using Size Contrast and Spatial Contrast instead of Harmony in Shabestani pattern.