The altar of Dionysus is located at Gregoriou the 5th street, quite close to the "Casa Romana" monument, on the same level with the Hellenistic Agora, approximately 3 meters below the level of the modern city.
It consitutes a typical example of a Hellenistic period altar of. The surviving part of the structure dates to the 2nd century BC, a time of prosperity for the city. It is assumed that the construction of the altar was sponsored by the king of Pergamon, in Asia Minor.
During the Byzantine period, the altar was abandoned and when the Knights conquered the island, they used several architectural parts of the building, such as cornerstones with bas reliefs on one or two sides for the building of the castle. These conrerstones were removed from the castle in 1958.
The frieze of the Altar depicts scenes from the Amazons as well as a group of Dionysean maenads, satyrs and silen. The frieze is preserved in a designated area within the castle.
The archaeological site of the altar of Dionysus also includes a Doric temple antis, probably dedicated to Dionysus and two rectangular structures one of which is considered to be a pedestal for a statue and the second either another pedestal or an older altar.
From the ancient altar, what remains today and can be seen by the visitor is a rectangular wall, which is actually the upper part of the temple's foundation, the entrance to the altar and part of a stone wall inside the altar.
Text Source: www.kos.gr