In north-western Iran’s city of Soltaniyeh, which was briefly the capital of Persia’s Ilkhanid dynasty (a branch of the Mongol dynasty) during the 14th century, stands the Mausoleum of Oljaytu, its stunning dome covered with turquoise-blue faience tiles. Constructed in 1302-12, the tomb of the eighth Ilkhanid ruler is the main feature remaining from the ancient city. The Mausoleum of Oljaytu is recognized as the architectural masterpiece of its period and an outstanding achievement in the development of Persian architecture, particularly in its innovative double-shelled dome and interior decoration.
The very large 50-m-high dome became an important reference for the later development of the Islamic dome. Similarly, the extremely rich interior of the mausoleum, which includes glazed tiles, brickwork, marquetry or designs in inlaid materials, stucco, and frescoes, illustrates an important movement towards more elaborate materials and themes. The Mausoleum of Oljaytu represents an outstanding achievement in the development of Persian architecture, particularly in the Ilkhanid period, characterised by its innovative engineering structure, spatial proportions, architectural forms, and the decorative patterns and techniques.
Excavations carried out in the 790-ha Mausoleum of Oljaytu property have revealed additional vestiges of the old city, and a large part of this property has retained its archaeological character. As the ancient capital of the Ilkhanid dynasty, Soltaniyeh represents an exceptional testimony to the history of the 13th and 14th centuries in Iran. Soltaniyeh was inscribed on the world heritage list of UNESCO in 2005.