Amin Saeidian et al./ Elixir His. Preserv. 52 (2012) 11190-11198 11190 Introduction Cover of the dome in Iran has a long history. The shortage of firm and oblong logs of woods, which were the main covering of the bed, caused the curved arch and dome to become widespread. Specifically, in the wider areas, the bed coverings were replaced by these domes [1]. In Dehkhoda dictionary, ourchin is defined as decoration, base, ladder, or stair. In Achaemenid period, the rich emperors of Iran supplied the structure of their palaces with the resistant woods from the trees, such as cedar from Lebanon or other far countries, by spending a good deal of money. Therefore, due to poor economic conditions, the need to spend a lot of money to provide wood, the absence of good climatic conditions to grow these types of woods in jungles and plains, and the availability of abundance of soil in Iran lands, curved arches and domes found their places as continental and structural phenomena in Iranian architecture [2]. In Sasanid period, the construction of the domes blossomed and became so prevalent that the structure and the construction method of the dome covering is used as the general model and instruction until now. [3]. The double-shelled vacant, double-shelled completely gaped, nar, rok, the combination of nar and rok, and ourchin domes are prominent examples of Iranian architecture [Table 11]. Ourchin domes are only found in the southwest part of Iran. Even in that part, they are scarce because this style of constructing the dome is different from that of northern and central parts of Iran and is exclusive to Iran. Further, only a limited number of this type of dome is found in Iraq. This very point indicates the uniqueness of this style of architecture [Table 12]. An Introduction To Ourchin Dome On the top parts of the dome, the consistent set-backs of the structure are located beneath. Normally, the height of the Tele: E-mail addresses: amino_saidiano@yahoo.com © 2012 Elixir All rights reserved Identifying the formation of ourchin dome, a symbol of tomb architectural structure in southern part of Iran Amin Saeidian 1 , Mojtaba Gholi 2 , Ehsan Zamani 3 , Mojtaba Ansari 3 and Mohamad Reza Bemanian 3 1 Department of Architecture, Mahshahr Branch, Islamic Azad University, Mahshahr [IRI]. 2 Department of Architecture, Faculty of Architecture, Jahad Daneshgahi Institution of Ahvaz Branch [IRI]. 3 Department of Architecture, Faculty of Art, University of Tarbiat Modares[IRI]. ABSTRACT The close relationship between religion and burial architecture as well as the special respect and reverence of Muslims to the holy shrines was the main reason of the development of burial architecture. Thus, the structure of such constructions is associated with holiness and symbolic values, on the one hand, and with the religious and political identity of the deceased person, on the other hand. Various types of dome such as rok, nar, and double-shelled have been introduced to the world and their functions have been investigated. In this architecture, ourchin dome, which is of typical characteristics of the tombs in southern part of Iran, has been neglected. Little information about this type of dome is available in the history of Iranian architecture. And this little information is limited to some reports and pictures from foreign tourists and unknown writers, including no more than a few names and dates of constructing of such structures. Therefore, the origin and the reason for the development of such domes as well as their role are still mysterious. In different parts of the present study, comparative, retrospective, and fieldwork studies have been used, whenever needed. In the current research, the root of the word, ourchin dome, and its meaning are pointed out. Also, the origin of Iranian architecture, which dates back to Seljuqid period, is introduced. Then, the geometric relationships of its sides are examined and different varieties of this dome [star and polygonal] are drawn. Studying the typology of the examples of this dome in Iran and Iraq revealed some remarkable points about the geometric, height, and shape of the dome, in addition to the number of its stories. Some factors, like the function of the crown, method of its construction, cover of the dome, and the system of the distribution of the load are clarified. Finally, by investigating the influential cultural and historical factors, we concluded that that the main reason for the development of the general structure of this type of dome was symbolic, not simply religious. This dome by its own or in combination with religious places has played an affective and functional role over time. © 2012 Elixir All rights reserved. ARTICLE INFO Article history: Received: 26 May 2012; Received in revised form: 13 October 2012; Accepted: 30 October 2012; Keywords Iranian architecture, Ourchin, Dome, Star, Polygonal, Mozaras . Elixir His. Preserv. 52 (2012) 11190-11198 Historic Preservation Available online at www.elixirpublishers.com (Elixir International Journal)