The Sultan Ahmed Mosque in Istanbul, popularly known as the Blue Mosque, was built between 1609 and 1616 during the rule of Ahmed I. Its popular name stems from the more than 20,000 hand-painted blue tiles that adorn its interior walls, featuring over 50 different tulip designs. The mosque is architecturally unique for its six minarets; at the time of its construction, only the Masjid al-Haram in Mecca had six, leading to a controversy that was resolved when the Sultan ordered a seventh minaret for the Mecca mosque. The design is the culmination of two centuries of both Ottoman mosque and Byzantine church development, incorporating some Byzantine elements of the neighboring Hagia Sophia with traditional Islamic architecture. Its massive central dome is supported by four 'elephant feet' pillars and is lit by over 200 stained glass windows.