his daily audience. Once the Lesser (Western) Palace of Al-Aziz Billah and a smaller palace Qasr Al-Bahr were built on the west side of the street, the Meidan (also spelled "Maydan") or center square completed the Fatimid Great Palaces and centralized the parade ground. The Meidan became known afterwards as "Bayn Al-Qasrayn", due to its location between the two palaces. The Bayn Al-Qasrayn area was also crossed by underground tunnels to which allowed the Caliph to travel back and forth between the palace and the caliphal gardens to the west. These private-use tunnels aided the caliph and royal officials to avoid larger-than-expected gatherings and to cross the area inconspicuously. The large-scale parade ground symbolized Fatimid success in trade and political control. This power was acknowledged in outer regions like Mecca and Medina, where the rulers in those areas allied to receive assistance and subsidies for protection and inclusion. The inclusion of everyday Muslims, Jews, and Copts to Fatimid daily life and royal presentations led to the palace guards closing the central throughway with chains during the nighttime hours to seclude and respect the Caliph as a leader for all. The square was also the site of various ceremonies and activities related to the dynasty. Social and artistic usages found in architectural decoration, court ritual, and open ceremony have been recorded through the Islamic dynasties of Cairo since the Fatimid Dynasty. Bayn al-Qasrayn was the center of life throughout the centuries of Fatimid control in Egypt. At its northern end, right above the Great Palace complex was the Aqmar Mosque. As the Fatimids were Shia Ismai'lis, this Fatimid Mosque became a piece of street architecture with its motifs and tributes to Allah, Muhammad and Ali on its daily attention attracting façade. This mosque became pivotal to teaching Shi'i Islamic religious concepts in the early twelfth century. Besides the royal, religious and state presentations on the parade grounds of Bayn Al-Qasrayn, the surrounding area had markets and businesses. The shops would pay dues via the waqf, a system of charitable endowments, that contributed to the functioning and progression of education and religious protection of Shi'i theology. This would include shops with food stuffs, armory bazaars, money changing and other widely diverse market fronts. Ayyubid and Mamluk development Over the subsequent centuries, Cairo developed into a full-scale urban center. After the end of the Fatimid Caliphate in the 12th century, the Ayyubid sultans