Islamic Cairo (), or Medieval Cairo, officially Historic Cairo (القاهرة التاريخية al-Qāhira tārīkhiyya) refers mostly to the areas of Cairo, Egypt, that were built from the Muslim conquest in 641 CE until the city's modern expansion in the 19th century during Khedive Ismail's rule, namely: the central parts within the old walled city, the historic cemeteries, the area around the Citadel of Cairo, parts of Bulaq, and Old Cairo () which dates back to Roman times and includes major Coptic Christian monuments. The name "Islamic" Cairo refers not to a greater prominence of Muslims in the area but rather to the city's rich history and heritage since its foundation in the early period of Islam, while distinguishing it from with the nearby Ancient Egyptian sites of Giza and Memphis. This area holds one of the largest and densest concentrations of historic architecture in the Islamic world. It is characterized by hundreds of mosques, tombs, madrasas, mansions, caravanserais, and fortifications dating from throughout the Islamic era of Egypt. In 1979, the United Nations Educational, Scientific and Cultural Organization (UNESCO) proclaimed Historic Cairo a World Cultural Heritage site, as "one of the world's oldest Islamic cities, with its famous mosques, madrasas, hammams and fountains" and "the new centre of the Islamic world, reaching its golden age in the 14th century." History The foundation of Fustat and the early Islamic era The history of Cairo begins, in essence, with the conquest of Egypt by Muslim Arabs in 640, under the commander 'Amr ibn al-'As. Although Alexandria was the capital of Egypt at that time (and had been throughout the Ptolemaic, Roman, and Byzantine periods), the Arab conquerors decided to establish a new city called Fustat to serve as the administrative capital and military garrison center of Egypt. The new city was located near a Roman-Byzantine fortress known as Babylon on the shores of the Nile (now located in Old Cairo), southwest of the later site of Cairo proper (see below). The choice of this location may have been due to several factors, including its slightly closer proximity to Arabia and Mecca, the fear of strong remaining Christian and Hellenistic influence in Alexandria, and Alexandria's vulnerability to Byzantine counteroffensives arriving by sea (which did indeed occur). Perhaps even more importantly, the location of Fustat at the intersection of Lower Egypt (the Nile Delta) and Upper Egypt (the Nile Valley further south) made it a