Analysis of information sources in references of the Wikipedia article "Derinkuyu" in English language version.
these excavations are referred to as long ago as the campaigns of Timour Beg, one of whose captains was sent to hunt out the inhabitants of Kaisariyeh, who had taken refuge in their underground dwellings, and was killed by an arrow shot through the hole in one of the doors.
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.