Built by Ahmed Ibn Tulun in 879 (265 H), the Ibn Tulun Mosque in the Sayyedah Zeinab district has an atmosphere of tranquillity unlike that of any other mosque in the city. Ahmed Ibn Tulun was sent to govern Cairo by the Abbasid Caliph in Baghdad, which explains the Mesopotamian influence. It is the oldest original mosque and the largest in Egypt. It incorporates a number of unique features, such as the external spiral staircase of the unusual minaret (the only one of its type in Egypt) which is similar to the famous Samarra Mosque in Mesopotamia.