Gods--the Persian religion was polytheistic headed by the principal god, Ahura-Mazda (supreme god of light represented as a winged disk) with whom the Persian king enjoyed an elevated and unique relationship. This made the Persian king a man above other men. However, contrary to Greek opinion (Aeschylus in particular), the Persian king was not a living god who embodied Ahura-Mazda or any other deity. Other gods representing the forces of nature included Mithra (sun and war), Zurvan (weather), Visai Baga (non-specific), Mizdusi (goddess of fertility and power), Naryasanga (fire worship), Brtakamya (unknown significance), Hvarira (rising sun) and Anahita (a goddess associated with lions). Sacrifices were offered that included animal and occasionally human victims. For instance, thousands of horses were offered to Mithra at his festivals.

Magi--the priests were known as Magi, originally a specific tribe of Persians. The magi presided over sacrifices and sacrificial fires, fire altars. Fire was treated with special reverence—no one was permitted to breath on it or burn anything dead or unclean. Human corpses were never burned. The magi also offered victims to lakes, rivers and springs, keeping the water pure and unpolluted.
The Magi were powerful figures at the court of the Persian king whose dreams they interpreted. Magi involved themselves in politics to the point of once usurping the throne after the death of Cambyses.

Zoroastrianism—the name Zarathustris appears on one treasury seal of the Achaemenid period. Almost nothing is known about Zoroastrianism at the time of Darius and Xerxes. The topic is sharply debated among scholars.

Festivals—the Persians had many festivals and ceremonies in which the king played a significant part. The New Year Festival every autumn in Persepolis was one of the most important. It featured a huge procession of the king and nobility, a great banquet and a lavish distribution of gifts by the king to his subjects.

Darius protected by Ahura-Mazda as he reviews prisoners