The Soltaniyeh Dome, built in the 14th century, is an architectural marvel showcasing the heritage of Zanjan, Iran. It is the third-largest dome in the world after the Florence Cathedral and Istanbul Hagia Sophia. The dome is located southwest of the Cohan Dej (Royal Citadel), a fortified area of 18 hectares at the center of the city of Soltaniyeh in Zanjan. 

Known for being the oldest double-shelled dome and the largest brick dome in the world, it distinctly stands out in the category of Islamic architecture. It paved the way for the construction of structures like the Santa Maria Cathedral in Florence and the Taj Mahal in India.

Soltaniyeh Dome, Zanjan: Complex of Ruins Sheet1
Soltaniyeh Dome ©

Historical significance

Soltaniyeh was briefly the capital of the Mongol Ilkhanid rulers in the 14th century. The dome was built as a mausoleum for the eighth Ilkanid ruler, Oljaytu, also known as Sultan Muhammad Khodabandeh. Though Oljaytu was baptized as a Christian, he practiced both Buddhism and Sunni Islam in his lifetime, before finally converting to Shi’a Islam. 

With his newfound faith in Islam, he wanted to establish a city that was large and powerful and the construction of this mausoleum was a symbol of this vision. At the orders of Oljaytu, the construction of the magnificent dome began and the process spanned ten years from 1302 to 1312. 

Soltaniyeh Dome, Zanjan: Complex of Ruins Sheet2
Soltaniyeh Dome Reflected Ceiling ©

The finesse in detailing and exquisite structural styling created a fresh architectural perspective, distinctly different from that of the previous Seljuk era. When the Soltaniyeh Dome was constructed, it was the tallest building in the world as the dome itself was a staggering 54 m tall, raising the standards for construction all across the globe. Rich patterns in the interior design reflect a prowess in craftsmanship and express a highly intricate level of beauty. 

Being a key monument in the development of Islamic architecture, Soltaniyeh became listed as a World Heritage site along with seventeen other cultural sites in 2005. 

Present-day Socio-cultural and Political Impact

The Soltaniyeh Dome is surrounded by a modest settlement with farmland all around it. Covered with stunning turquoise-blue tiles, the dome itself is a bright pop of colour in the urban landscape, prominently more noticeable from the rest of the features at first glance. The 8 minarets that surround it become the next focus of one’s attention. 

The architectural heritage of Soltaniyeh is in many ways a physical manifestation that speaks for the history of the city, by merely existing as an imprint left by their great ancestors. Therefore, the present-day communities surrounding it attain a social and cultural identity that arises from its association with the old city. 

Soltaniyeh Dome, Zanjan: Complex of Ruins Sheet3
Soltaniyeh Dome Aerial View ©

Being centrally located, the structure stands out in the city as the only remains of the ancient kingdom. The economic impact of the dome which acts as a backdrop to the settlement is that it attracts foreigners into the city and additional revenue is obtained from tourism at the state level. After being registered as a world heritage site by UNESCO, the building has been seeing tourists not only from Iran but from all over the world every year, to observe and study the sensational phenomenon that it is. Thus, the existing built fabric encompassing the dome also gets an additional benefit through the political realm.

Soltaniyeh Dome, Zanjan: Complex of Ruins Sheet4
Soltaniyeh Dome Interior Detailing ©

Building Composition and Style 

The Soltaniyeh Dome is octagonally shaped with eight doors and eight porches, and each side has a length of about 80 meters. Gypsum was the chief building material used for the construction and limestone was also used to a comparatively lesser proportion. The lower building consists of three main sections namely the main entrance, the mausoleum (tomb), and the crypt, while the upper portion of the building has pavilions and rooms. 

Torbat Khaneh, on the southern side of the structure, is where sacred soil was used for construction. Oljaytu used soil from Najaf, a city in Iran considered sacred by Shi’a Muslims. The Sardabeh, the portion where Oljaytu was buried, is located below this. 

Soltaniyeh Dome, Zanjan: Complex of Ruins Sheet5
Soltaniyeh Dome Interiors ©

The double-shelled earthquake-resistant dome weighing 200 tons, is formed by two separate parallel layers of brick that are joined together through the buttresses. The interiors of the Soltaniyeh Dome were decorated with faience tiles, colored bricks, and decorative plasterwork. Calligraphic writing of verses from the Quran and Hadith can be observed on the sides of the ceiling. Various types of intricate tiling, stucco designing, stucco and brick stalactites, wooden and stone carvings, and lattice brickwork were used. 

The craftsmanship employed in this heritage structure has a universal as well as timeless quality to it. The use of turquoise-blue and ultramarine-blue in the burl designs add to the exquisiteness. A sundial was incorporated in the design, most likely to follow the timings for the religious performances.

Soltaniyeh Dome, Zanjan: Complex of Ruins Sheet6
Soltaniyeh Dome ©

The Soltaniyeh Dome, particularly its exterior decorations, faced damages many times during its long lifetime, and hence preservation and conservation are very crucial for its future to protect its integrity. Comparatively, the interior design has remained largely intact. Urbanization around the dome is considered a possible future threat to the universal value of the heritage structure. 

Being owned by the state, efforts are being made for its protection based on the ‘Iranian Law on the Conservation of National Monuments’ in 1982. The management plan includes objectives concerning the research, restoration, and conservation of the heritage as well as the development of tourism at Soltaniyeh.


  • Dome of Soltaniyeh, Iran
    Available at:
    [Accessed 1st June 2021].
  • Dome of Soltaniyeh
    Available at:
    [Accessed 1tst June 2021].
  • (2019). Zanjan’s Soltaniyeh; world’s largest brick dome
    Available at:
    [Accessed 1st June 2021].
  • Kalantari, H., Nasserasadi, K., Aliasghar Arjmandi, S. (2018). Seismic vulnerability study of Soltaniyeh dome using nonlinear static and dynamic analyses
    Available at:
    [Accessed 1st June 2021].
  • Soltaniyeh Dome – Zanjan
    Available at:
    [Accessed 2nd June 2021].
  • Soltaniyeh
    Available at:
    [Accessed 2nd June 2021].
  • (2005). Mostar, Macao and Biblical vestiges in Israel are among the 17 cultural sites inscribed on UNESCO’s World Heritage List Available at: [Accessed 2nd June 2021].
  • Zanjan,Iran
    Available at:,_Iran
    [Accessed 2nd June 2021].
  • Ilkhanate
    Available at:
    [Accessed 2nd June 2021].

Devaki Kesh is an architect passionate about regenerative building techniques and revival of urban landscapes. She is a lifelong learner and loves to express herself through writing, art and music. She is a mother to five cats and two dogs.