During the caliphate of Umar, many new cities were founded. These included Kufa, Basra, and Fustat. These cities were laid out according to the principles of urban planning. All streets in these cities led to the Friday mosque, which was sited in the center of the city. Markets were established at convenient points, which were overseen by market officers charged with ensuring the quality of goods. The cities were divided into quarters, and each quarter was reserved for particular tribes. During the reign of Umar, there were restrictions on the construction of palatial buildings by the rich and elites—symbolic of the egalitarian society of Islam, where all were equal—although the restrictions were later revoked by Uthman because of the rise in the overall standard of living, and the construction of two-story buildings was permitted. As a result, many palatial buildings were constructed throughout the empire, including Uthman's huge palace in Medina, "Al-Zawar", constructed from his personal resources.