There are around 200 separate underground settlements in Cappadocia. Although evidences of Prehistoric life have been found in the area, it is not known whether the underground settlements had any connection with that age.
The earliest record of the underground settlements is to be found in Xenophon's "Anabasis" According to this book, Hellenic communities stayed in the underground settlements of Kaymakli and Derinkuyu, which makes it possible to date the cities back as early as the end of the 4th century BC. There is also evidence that the development of the underground settlements owes much to the Hittites. Rock imprints and inscribed monuments on the rocks from the Hittite Empire and the Neo-Hittite period, the presence of underground passages, known as "Potern", which were used in the defense systems of the Hittite towns, and the superior building techniques are all evidence of Hittite involvement. The secret tunnels found in Hittite citiecappadocia undergorund citiess were generally used to ambush attackers, and for defense.
If the Hittites did carve out these settlements for military purposes, it is quite normal that no artifacts from that time have been found. Besides this, dwellers coming after the Hittites would have removed any such traces.
Objects found in the settlements belong to the Byzantine period, that is the 5th to 10th centuries AD. The number of underground settlements used for defense and for religious purposes increased during this period.
The Arab-Sassanid raids, which began in the 7th century, forced Christian communities to use these underground settlements as refuges.
As the Caravanserai in Cappadocia are found within 5-10km of the underground settlements, it is also supposed that the Seljuk used these settlements as dwellings or for military purposes. For example, Dolayhan Caravanserai is near to Til Köy underground settlement, and Saruhan is near to Ozkonak.
Important underground settlements are, Kaymakli, Derinkuyu, Mazi, Ozluce, Ozkonak, Tatlarin, Kurugol and Gokçetoprak.