The mausoleum of Oljaytu was constructed in 1302–12 in the city of Soltaniyeh, the capital of the Ilkhanid dynasty, which was founded by the Mongols. Soltaniyeh is one of the outstanding examples of the achievements of Persian architecture and a key monument in the development of its Islamic architecture. This eight-towered octagonal building, built for a Mongol sultan, supports a brilliant turquoise-brick dome, one of the world’s largest. The interior is full of scaffolding, but spiral stairs lead up through thick walls to airy terraces with exceptional views, beautiful vaulted ceilings and fine mosaics. Oljeitu was a Mongol ruler who, after dabbling in various religions, adopted the Shia name Mohammed Khodabandeh. He had planned to rehouse in his mausoleum the remains of Imam Ali, son-in-law of the Prophet Mohammed.