Uplistsikhe (უფლისციხე = prince’s fortress) is an ancient rock-hewn town in central Georgia, near Gori city in Shida Kartli. Built on a high rocky left bank of the Mtkvari River, it contains various structures dating from the 5th century BC to the Late Middle Ages, and is notable for the unique combination of various styles of rock-cut cultures, as well as the co-existence of pagan and Christian architecture. Uplistsikhe is identified as one of the oldest urban settlements in Georgia. Strategically located in the heartland of ancient kingdom of Kartli. Prior to the introduction of Christianity to Georgia in the 4th century, Uplistsikhe was a prominent pagan holy place and the 9th century brick church of Uplistulis Eklesia (Prince's Church) was built directly over a pagan sun temple. During the early Middle Ages, when the city was at its peak of development, there was a population of some 20,000 living in the 700 caves (of which only 150 remain). However, Uplistsikhe reemerged as a principal Georgian stronghold during the Muslim conquest of Tbilisi in the 8th and 9th century. In the 13-14th century Mongol invasions devastated the city and a series of earthquakes contributed to its eventual abandonment.