Marrakesh was the most important imperial city. The city was founded in 1062 by Abu Bakr ibn Umar. In the 12th century, the Almoravids built many Koranic schools (madrasas) and mosques (Andalusian style). The red walls of the city and buildings constructed in red sandstone, have given the city the nickname of ‘Red City’. The mausoleum comprises the interments of about 60 members of the Saadi Dynasty (Saadian Tombs). Among the graves are those of Ahmad al-Mansur and his family. Especially the Italian Carrara marble and gilding honeycomb muqarnas (decorative plasterwork) with pure gold make the Chamber of the 12 Pillars a suitably mausoleum.