DACIAN RIDERS. The so-called Dacian Riders were associated with a mystery religion of the Getae and the Dacians, peoples of Thracian stock who lived in ancient Dacia (roughly equivalent to modern-day Romania). The cult of the Dacian, or Danubian, Riders began to spread among Roman soldiers soon after 106 CE, when Dacia was conquered by Trajan and made a province of the Roman Empire. Traces of the cult have been found as far away as the Roman provinces of Gaul and Britain.

Numerous reliefs and gems depicting the Dacian Riders are extant. Of the 232 items catalogued by Dumitru Tudor (1969–1976), 60 were found in Dacia, 24 in Moesia Superior, 34 in Moesia Inferior, 47 in Pannonia Inferior, and 25 in Pannonia Superior. Most of the Dacian reliefs are made of marble. They were copied on a large scale in lead, a very expensive material whose use can be explained only by the magical...