Scienceline Publications Journal of Civil Engineering and Urbanism 2252-0430 8 4 2018 July The Manifestation of Geometric Principles in the Traditional Architecture of the Monasteries; Case Study: Sheikh Shahab Al-Din Ahari Tomb and its Hidden Geometry 44 53 ojceu.com/main/attachments/article/65/J.%20Civil%20Eng.%20Urban.%208%20(4)%2044-53,%202018.pdf EN Zeinab Nazer Master of Architecture, Faculty of Architecture and Urban Design, Tabriz Islamic Art University, Iran Ahad Ahad Associate professor of Tabriz Islamic Art University, Iran The tomb of Sheikh Shahab al-Din Ahari was built in the 6th century AH and its evolution has taken place in the periods of the Ilkhani, Timurid, Safavid periods. Sheikh Shahab al-Din Ahari was the master of Sheikh Safi al-Din Ardebili (the Safavid's father). Because of the Safavids, they had a special respect for him, And there are manuscripts around the walls of the mosque of Sheikh Bahai, Shah Abbas III, Abolghasem Nabati, which shows the significance of this monastery during the Safavid period and before it. The unique features of the architecture suggest that the architect used the construction of geometric principles and the exact system of Iranian proportions. And considering that the study of the geometry of the Sheikh Shahab al-Din Ahari monastery, the tomb since the Ilkhanid era in East Azerbaijan, has not been carried out and because of the lack of clear exploratory resources some researches required considering the importance of the subject, geometric proportional analysis approach that seek to answer this question: which role geometry has played in the construction and development of the spatial elements of the monastery? Therefore, the study of analytical research and data collection tool to collect data and information have been used both field observations and library, and in order to revisit the geometric principles and proportions in this collection, geometrical analysis was carried out using geometric analysis, plan, facade and sectional analysis. The results of the analysis indicated that the architect of the building has had the required knowledge of the geometrical proportions and geometry systems that has used theme in selecting the scale of the construction and location of the main spaces, such as: large space under the dome (known as Ghosh khaneh), Chinese houses (Chinikhaneh), courtyard, Eyvan (porch) with two minarets and two small booth of two sides of the floor. The unveiling of hidden geometry in the design of the building reminds us of the privileged position of geometry in traditional architectural design, which helps to better understand traditional architecture. Sacred Geometry Iranian Architecture Structural Design