Marble group of Mithras slaying the bull

The cult of Mithras originated in Persia, but he was one of a number of eastern deities, including Cybele and Isis, whose worship spread throughout the Roman Empire during the first three centuries AD. He is shown here in eastern costume, including trousers and a Phrygian cap. He is killing a bull, the spilling of whose blood was believed to bring about the rebirth of light and life. The dog and the snake which try to lick the blood both feature prominently in Persian religious imagery, as does the scorpion which attacks the bull's genitals.

After a secret initiation, the devotees of the cult of Mithras rose through ranks such as 'soldier', 'raven' and, ultimately, 'father'. They consumed bread and water (as the 'meat' and 'blood' of the bull) at communal meals. This, combined with the cult's emphasis on regeneration, earned them the particular enmity of the Christians. Mithraism's popularity lay partly in its appeal to the army, but like all mystery religions (including Christianity) it benefited from ideological and philosophical changes in the Late Empire; these tended towards monotheism - the worship of a single god.