Study the Evolution and Continuity of Chahartaqy Architecture in North East Iran from Sassanid Period until the End of the Fourth Century AH

Form plays a major role in Iranian architecture. Chahārtāqy is a type of common forms in Iranian architecture with an ancient history that by studying its structure and formation process and development, the course of development and continuity of architecture in various eras in Iran can be understood. From a number of researcher's view, Khorasan is the origin of Chahārtāqy architecture, Chalipaee form (cruciform), and Chahar Eyvani (four-porch) plan. The authors of the paper, according to this approach have studied the evolution and continuity of Chahartaqy form from Sassanid era in the North East Iran until the end of the fourth century AH. So, in this article we are going to make it clear that how was the distribution of Chahartaqys in North East of Iran and how was their applied categorization? In addition, what was the relationship between the location of Chahartaqys and their application? And what has influenced their form and structure? Finally what was the impact of Chahartaqyhays of Sasanian in North East of Iran on Islamic architecture of the region in that period? This research has been carried out with the descriptive-analytical method and by means of compilation of information, field studies, and library studies. The results suggest that both religion and politics have played a major role in the formation and development of this type of architecture. The Location of Chahartaqys also has had a direct effect on the type of construction, and similarly, the Islamic period architecture of the region of North-Eastern Iran, especially in such edifices as mausoleums, mosques, palaces, mansions, and fortresses has been influenced by the Sassanid Chahārtāqy plan and the general form of construction of that period.