The Sultan Ahmet Mosque, commonly called the Blue Mosque, is a mosque in Istanbul, Turkey. It was built between 1609 and 1616, when Ahmet I ruled the Ottoman Empire. Like with many other mosques, the founder of the mosque is buried in it. His architect, Sedefkar Mehmet Agha, decorated it like a jeweler would. There is also a madrasah and a hospice associated with the mosque. Today it is one of the greatest tourist attractions in Istanbul.