As far as their religion is concerned, part of the Thracians practiced the so-called Thracian Orphism - a teaching related to the cult of Orpheus and followed by the aristocracy, organized in mysterious male societies.
In the roots of Thracian Orphism stood the idea of self-perfection and the system functioned on two levels: aristocratic (doctrinal) and popular (social). The aristocratic level concerned those initiated into the secret knowledge of the teaching, while the popular level was connected with people familiar with the teaching but not initiated in it.
Thracian Orphism combined the cult of the Earth and the cult of the Sun, personified by Orpheus and Zalmoxis. According to the cosmological model of Thracian Orphism, the world is structured in a seven or ten-stage cycle:
1. Self-fertilization of the Great Goddess-Mother (Earth).
Here is what Herodotus writes about the homage of the Thracians to Zalmoxis: ,,Thracians believe that they don't die but that the dead person goes to god Zalmoxis. Every five years, by casting lots, they chose among themselves a messenger to Zalmoxis and every time they ask for what they need. They send the messenger in this way: several of them, chosen for the purpose, hold up three spears. Others, by gripping the hands and the feet of the messenger, hold him up high, sway him and throw him onto the spearheads. If he dies being pierced by the spears, they believe the god is benevolent. If he doesn't die, they reprimand the messenger for being a bad man. After that they chose another messenger. They make their orders while he is still alive. The Thracians also shoot their arrows up to the sky, against thunder and lightning, threatening the god and believing there is only one god - theirs".
In addition to Zalmoxis, the Thracians also worshiped Bendida - the goddess of hunting and fertility, Sabazius - the god of wine and merriment. The cults to Greek deities also spread among the Thracians and they were given Thracian names. The prayers and sacrifices were performed in sanctuaries especially built for the purpose by the Thracian priests. The sanctuary of god Dionysus in the western Rhodopes was famous in Antiquity.
The major figure in Thracian mythology is the well-known singer and musician Orpheus. According to ancient authors, with his songs he cast a spell on the mountains, the hard rocks and the waters of the rivers. Orpheus brought together groups of men initiated into the sacrament for special rituals with music, songs and dancing. The Orphic cult also spread in Ancient Greece.
Here is how the Greek writer Conon (1st c. B.C. - 1st c. A.D.) describes Orpheus in a mythological story: ,,Orpheus reigned over the oppressed land. He practiced music and singing accompanied by a lyre. This made him very popular among the people since the Thracians loved music. He became popular with the story of having gone down to hell for love of his wife Eurydice. He was also very good at enchanting people with his songs and the animals and the birds of prey, the trees and even the stones followed him willingly. He died torn to pieces by Thracian women because he didn't allow them to take part in the orgies. When their country was devastated by starvation, they prayed for the awful scourge to stop and received an omen that they would be freed from evil if they found and buried Orpheus' head. They found it with great difficulty. The head was still singing and was not damaged by the sea. So they took it and buried it under a large mound, which they encircled with a sacred yard".
In Antiquity the Thracians offered sacrifice to the natural elements. The rituals were performed at various places - in caves and near rocks of queer forms. Gradually cults of different deities appeared. Among them very important place was attributed to the Thracian Rider - Heros. He became the only anonymous deity of the Thracians. His image can be found on the numerous votive tablets in the sanctuaries dedicated to him near almost all settlements. He was called with the Greek epithet ,,kirios", i.e. master, and personified the Thracian belief in immortality. He is depicted in hunting scenes, most often following a wild boar and accompanied by a dog and a lion. Such an iconography defines him also as the protector of all nature and the victor of evil.
Perperek, Perperikon, Hiperperikon or the ,,Sacred town of the Thracians" is situated in the Eastern Rhodopes, 15 km off the town of Kurdzhali. It used to be the capital of a lost civilization, provisionally called ,,The rock people" by archeologists. Mentions of the fortress can be found in the Byzantine chronicles of George Acropolitis and John Kantakuzin in connection with the wars between Bulgaria and Byzantium in 13th- 14th c. The fortress and the town are connected with the ore deposits and the extraction of gold in the region. They appeared in the place of the Thracian royal and religious centre, probably belonging to the Odrysai (6th c. B.C.). We find remains of a castle (tursis) with its lower part cut into the rock and cult installations - a pool. A church was erected in early Christianity. According to some theories based on the rock paintings, the place is related to the cult of the proto-Bulgarian goddess Umai, who personifies the female principle and is known as the wife of Tangra. What has remained from the mediaeval fortress are parts of the walls, an octagonal tower and reservoirs cut into the rock.
Perperikon is rich in archeological finds. There are no bright objects of gold and silver of prehistoric times but there are magnificent pieces of ceramic of the Late Bronze period. In the skirts of the town was found one of the earliest Thracian silver coins dated back to 5th c. B.C. Impressive are the objects of luxury of the Roman period (1st - 4th c.). In the foot of Perperikon was found a piece from a figurine of the Thracian Rider dated 1st - 2nd c., a unique silver ring from 2nd - 3rd c. on which is mounted an image made of the semiprecious stone carneol. On the stone is inscribed a beautiful image of the god of the Sun, Helios, driving a four-horse chariot - quadriga. On an oval bronze plate is imprinted the image of Heracles, wrapped in lion's skin and leaning on his famous staff. Most numerous are the gold objects of late Antiquity (5th - 6th c.): a fragment of a patrician rank diadem, a coin of Emperor Justin (518 - 527), numerous beautiful ceramic vessels and many coins. To the middle ages belong the collection of lead seals and more than 20 bronze crosses of various sizes.