the 6th c. BC. Middle Ages From the 6th century the city was under the control of the Byzantine Empire. By order of Emperor Justinian I, a citadel named Bospor was built there. Bospor was the centre of a bishopric, the diocese of Bosporus and developed under the influence of Greek Christianity. In 576, it withstood a siege by the Göktürks under Bokhan, aided by Anagai, the last khan (ruler) of the Uturgurs (tribe of Huns). In the 7th century, the Turkic Khazars took control of Bospor, and the city was named Karcha from Turkic "karşı" meaning 'opposite, facing.' The main local government official during Khazar times was the tudun. Christianity was a major religion in Kerch during the period of Khazar rule. Kerch's Church of St. John the Baptist was founded in 717; thus, it is the oldest church in Ukraine. The "Church of the Apostles" existed during the late 8th and early 9th centuries, according to the "Life of the Apostle Andrew" by Epiphanius of Salamis. Following the fall of Khazaria to Kievan Rus' in the late 10th century, Kerch became the centre of a Khazar successor-state. Its ruler, Georgius Tzul, was deposed by a Byzantine-Rus expedition in 1016. From the 10th century, the city was a Slavic settlement named Korchev, which belonged to the Tmutarakan principality. Kerch was a center of trade between Russia', Crimea, Caucasus and the Orient. In the 13th century, Crimea including Korchev was invaded by Mongols. After the Mongols, the city became the Genoese colony of Cerco (Cherkio) in 1318 and served as a sea harbour, where townspeople worked at salt works and fishery. In 1475, the city was passed to the Ottoman Empire. During the Turkish rule Kerch fell into decay and served as a slave-market. It repeatedly suffered from raids of Zaporizhian Cossacks. 18th–20th centuries In response to the strengthening of Russian military forces in Azov area, the Turks built a fortress, named Yenikale, near Kerch on the shore of Kerch Strait. The fortress was completed by 1706. In 1771 the Imperial Russian Army invaded Crimea and approached Yenikale. The Turks decided to abandon the fortress, though reinforcements from the Ottoman Empire had arrived a few days earlier. By the Peace Treaty of Kuchuk-Kainarji in 1774, Kerch and Yenikale were ceded to Russia. As a result, the Turkish heritage has been almost completely wiped out. In 1790 Russian naval forces under