A mithraeum was a place of worship dedicated to the ancient Roman god Mithras, a deity associated with the sun, light, and contracts. Mithraism was a mystery religion that gained popularity in the Roman Empire from the 1st to the 4th century CE. Mithraeums were typically small, underground temples or caves, and they featured ritualistic depictions of Mithras slaying a bull, a central theme in Mithraic iconography. The religion was exclusive to men and had a strong influence on Roman soldiers and merchants. The exact beliefs and practices of Mithraism remain somewhat mysterious, as much of its knowledge was transmitted through secret rites accessible only to initiates.