The relief of Mithras Killing the Bull in Thermes is located on a rock southeast of the village. It became known in 1973, following investigations by the Ephorate of Antiquities. The relief is 1.07 m high and 1.12 m wide at the base.

The relief depicts god Mithras killing the sacred bull in an arched framework. He is clothed in Persian costume (kandys), short tunic and chlamys and is wearing a Phrygian cap (pilos). He is kneeling with the left leg on the bull, holding the animal probably by the nostrils with his left hand, and stabbing it with his right hand. The followers of god, two torch-bearers, are on each side, dressed like Mithras; Cautes with his torch pointing up and Cautopates with his torch pointing down. Under the bull, a snake is reaching the blood of sacrifice. Between Cautes and the head of the bull there is another iconographical motif; the so-called ?rock-birth? scene of Mithras. This shows Mithras emerging from the top of a rock, holding a torch and a knife. There is an unidentified form, perhaps a bust of the Sun, above the main scene.

Τhere is a series of subsidiary scenes, at the bottom of the central tauroctony, illustrating events from the Mithras narrative into eight small arched frames. They are associated with the initiation stages of believers or the benefactions of god: Mithras as Atlas holding the Earth, as archer making water spring with his arrow, the hunting and riding of the bull, meeting Sol (the Sun) who kneels to him, sharing a sacred meal of bull-parts with Sol, and ascending to the heavens in a chariot (glorification).

Μithras was a secondary deity in the ancient Iranian religion. The term Mithras is derived from the Zoroastrian Avesta and it was adapted into Greek as Mithras. All of our information is derived from numerous archeological finds.

The Greek biographer Plutarch (46-127 AD) says that the pirates of Cilicia, were the ones who brought the practice of Mithraic rituals to Rome in his days. The theory that Mithras was merely the Roman form of the ancient Persian deity Mitra was abandoned by the modern studies which favored a roman origin for the cult. Μithraism was created in Rome by a single founder who had some knowledge of both Greek and oriental religion. In the Roman Times the name of the god was linked to a new and distinctive imagery and the cult of Mithras expanded and had become very much in vogue in the Roman Empire.

The mysteries were popular among the legions. The temples of Mithras (Mithraea) were frequently underground places, caves or chambers. A relief or a fresco of Mithras Κilling the Βull dominated in the end of the main aisle. In the mysteries of the cult only males participated. There were seven stages of initiation. Different ritual meals were associated with each stage, the details of which are unknown.

A lot of scholars refer to common elements such as the initiation ceremony, the use of water, the sacred meal, the birth of the god on December 25, Sunday as a day of worship and the character of salvation.

The relief of Mithras at Thermes is connected with a small fortress of the 2nd-3rd c. AD in the nearby hill Stithoma, where there was probably a military settlement to control the natural passage that follows the stream of Thermes. Indications for mines and the thermal sources support the argument for the presence of the Roman garrison in the area.