In 1396, Ottoman Sultan Bayezid I defeated Eastern European crusaders at the Battle of Nicopolis. To commemorate his victory, Bayezid commissioned architect Ali Neccar to design and build the Grand Mosque of Bursa. Construction took place between 1396 and 1399. The mosque is located in the bazaar district of Bursa, Turkey. It was renovated from 2008 to 2010, and it is also a UNESCO World Heritage Site. The most prominent feature of the Grand Mosque of Bursa is the twenty domes on its roof. Supposedly, Bayezidi originally wanted to build twenty mosques to celebrate his victory but decided to construct one mosque with twenty domes at his son-in-law’s, Emir Sultan, suggestion. Inside the mosque is the massive Prayer Hall, which has a 3,6165.5 square foot surface area. Neccar designed pillars to divide it up the hall and make the hall seem more private. The Prayer Hall center also contains the 18-sided Ablutions Fountain, which sits underneath the open dome; the fountain was added in the 1800s. Other famous features of the Grand Mosque of Bursa include the Mihrab and the 192 calligraphy inscriptions, most of which were created between 1778 and 1938.