There is an interesting mosque complex next to Bab Zuweila built by the Mamluk Sultan al-Mu'ayyad Saif al-Din Sheikh and completed in 1421; The complex includes the mosque, shrines, and religious schools; The Sultan Al-Muayyad Mosque is located on the site of a former prison where Al-Muayyad himself was once held. It is said that while in prison he suffered so much that he swore that if he survived he would build a place for religious learning on the site of the prison, and the complex became one of the most important centers for learning Shafi'i jurisprudence; If you are in Cairo, you must visit this wonderful mosque and learn about its history.