Some Considerations on Employing Passive Defense Principles in the Construction of Castle-City in the Ancient Iran

Human residential units have always been exposed to damages resulting from natural disasters and man-produced incidents. So، human has always been trying to adopt various methods to reduce the damaging impacts of these types of disasters in his living environment. One of the innovative approaches was the use of passive defense to reduce the vulnerability of residential units. Since Iran territory ahs always been located at the road of historical events and exposed to military aggression of different nations and neighboring tribes، so that using the features of natural geography has always been noticed as a way to protect the security of the people. One of the most important manifestation of these issues can be seen in the construction of castles or military and non-military castles in the heights. This article is an attempt to identify the basic features of the most important manifestation of human residential unit including castles in the ancient Iran from the perspective of passive defense. For this purpose، using the descriptive and analytical methods، this article extracts the most important characteristics of Iranian castles in three historical periods of Medes، Ashkanian and Sassanids. The results of this research indicates that from the viewpoint of military commanders، architects and engineers of the ancient Iran، the principle of locating and using geographical barriers have been in the blueprint of passive defense in every three periods. Considering the extracted features of castles of these three periods، it can be understood that the considerations of passive defense in each period had a growing trend such that in the last periods under our consideration، the new and complex methods of passive defense encircles the castles.