Soltanieh was built in the 14th century as the capital of the Ilkhanid dynasty, founded by Mongols of Iran. The city lies approximately 240 kilometres from Teheran.
A UNESCO World Heritage site since 2005, Soltanieh’s most important building is the mausoleum of Oljaytu, erected between 1302 and 1312. The mausoleum represents one of the best examples of the Persian architecture of the period and also demonstrates the development of the Islamic architectural tradition. The mausoleum is an octagonal building with a 50 metre high brick dome: this is the oldest double-shell dome in Iran and one of the largest brick domes in the world. It is surrounded by eight minarets and covered by turquoise faience. Spectacular though it is, the original appearance would have been grander still as some mosaics, faience decoration, and murals have been lost. The interior of the mausoleum is also richly decorated and has even been described as ‘anticipating the Taj Mahal’ (A.U. Pope).
The double-shell structure of the mausoleum and the complex use of materials for its decoration made it an essential step in the history and development of the Islamic architecture of central and western Asia. These were innovating architectural, decorative and engineering techniques for the time and hallmarks of the Ilkhanid period of the 13th and 14th centuries.