From Byzantine times (4th century CE) through 1923 Derinkuyu was known by its Cappadocian Greek inhabitants as Malakopea (). The underground city was greatly expanded in the middle Byzantine period to serve as a refuge from the raids of the Umayyad Arab and Abbasid armies, during the Arab–Byzantine wars (780-1180). The city contained food stores, kitchens, stalls, churches, wine and oil presses, ventilation shafts, wells, and a religious school. The Derinkuyu underground city has at least eight levels and depth of 85 m and could have sheltered thousands of people. The city continued to be used as protection from the Mongolian incursions of Timur in the 14th century. After the region fell to the Ottomans the cities were used as refuges (Greek: καταφύγια). As late as the 20th century the town's inhabitants, called Cappadocian Greeks, were still using the underground chambers to escape periodic waves of Ottoman persecution. (The Cambridge linguist Dawkins, who spent time in the towns from 1910-1911 while writing his book on Cappadocian Greek wrote, "their use as places of refuge in time of danger is indicated by their name καταφύγια, and when the news came of the recent massacres at Adana [in 1909], a great part of the population at Axo took refuge in these underground chambers, and for some nights did not venture to sleep above ground.") When the Cappadocian Greeks were required to leave in 1923 in the Population exchange between Greece and Turkey the tunnels were finally abandoned.