Al-Azhar was founded by the Fatimid caliphate in 970 and completed in 972, making it the oldest continuously operating mosque in Cairo. The teaching circles that grew around it became Al-Azhar University, and the mosque remains the seat of the Grand Imam of Al-Azhar, whose rulings carry weight across much of the Sunni world. It sits in the historic Islamic quarter of the city and holds daily and Friday prayers alongside its teaching function.