Gonio Fortress (previously called Apsaros or Apsaruntos), is the oldest fortress in Georgia. The name derives from one of the characters of the myth of the Argonauts (Apsaros = brother of Medea). The earliest archeological layers date back to the 8th and 7th century BC. A cemetery of the 5th century BC, south of the castle, was established by the Colchic kingdom (one of the Georgian kingdoms). Plinius II was the first to mention Apsirtus in the 1st century AD. In the second half of the 1st AD, the high walls were built. Gonio became a center of roman culture and imperial power (with up to 1500 soldiers) until the 4th century, featuring a theater and a hippodrome. In the mid 6th century, Gonio became a byzantine stronghold, in the 12th century a part of the Georgian kingdom. In the 16th century, an ottoman garrison was stationed in Gonio. After the Russian-Turkish war of 1877-78 Gonio became Georgian again. The total length of the fortress walls is 900 meters.