The Thracians had no written language. All information about them—including their beliefs—comes from their neighbors, the Hellenes (the ancient Greeks). Some Thracian beliefs seemed familiar to the Greeks, while others appeared strange. We also learn about Thracian gods and cults from scenes depicted on vessels, jewelry, horse ornaments, and tomb murals.

The Thracians believed the gods were everywhere around them. They imagined them in their own image—people with red hair and blue eyes. Among the most ancient beliefs, dating back to prehistoric times, was the worship of the Great Mother Goddess: Bendida, the goddess of fertility.

The Sun was also worshipped as a deity. In its honor, a sacred fire burned continuously in the household hearth.

The ancient Greek historian Herodotus describes Zagreus as a deity revered by all Thracians—a lord of nature and master of the elements. The Hellenes knew this deity better as Dionysus. The Thracians later worshipped him under this name, especially during the Roman era, as a patron of fertility and viticulture. He was typically depicted wearing a vine wreath. Celebrations in his honor featured wine drinking.

Thracians and Hellenes borrowed deities from each other. When the Greeks described Thracian gods and rituals, they often used the names of their own familiar deities.

Herodotus mentions Ares, Dionysus, and Artemis as Thracian gods. Thracian kings traced their ancestry to Hermes, the patron god of herds. On coins of the Thracian tribe Deroni, Hermes appears with a staff, leading a pair of oxen or presenting the yoke to the ruler as recognition of his authority.

In Thrace, the image of Ares as the god of war likely merged with the more widespread cult of the Thracian Horseman. The Thracian Horseman represents the Thracian ruler, who was simultaneously king, priest, and god. This figure appears on numerous Thracian artifacts, including vessels, horse harness ornaments, and rings. The appliqués from the Lukovit and Letnitsa treasures are among the most famous examples.