While the exact date of construction is not known, it is believed that either the Phrygians or the Hitties were the first to inhabit the Derinkuyu. The Turkish Government’s stance on the issue is that the Phrygians were the first to settle in the 7th-8th Centuries B.C.The Phyrigians were known for their architecture, leading for many scholars to believe that they were some of the ones that helped to construct the caves and tunnels. The Hittie civilization was in control of the region in Turkey where Derinkuyu is located. Archaeological finds have shown that the Hitties sought out Derinkuyu as a place of refuge from the Thrace Empire that was invading during the 12th century B.C. The Persian book “Vendidad” also mentions that the King Yima ordered “flocks, herd, and men” into underground tunnels, perhaps meaning the city of Derinkuyu. Later, Christians would use the caves for refuge from religious persecution from the Romans. Making the tunnels larger and adding new rooms, such as sanctuaries. There are tunnels connecting Derinkuyu to other underground cities, allowing trade and protection to be available to the city.