The Church of St. Martyr George is a Bulgarian church in the old part of the city of Sozopol. It was the cathedral of the Diocese of Sozopol. It contains a number of valuable icons dating back to the second half of the nineteenth century. It also contains the relics of St. John the Baptist. located on St. John's Island, as well as some other Christian relics, as part of the Holy Cross and part of St. Andrew I.