Though mysteries as such were rare in Roman religion, the Romans, thanks to their cultural and political contact with the Hellenistic world, were familiar with Eastern religions and gave them an enthusiastic welcome. They took a particular interest in the cult of Magna Mater, the personification of fertility. The Egyptian Isis, Phrygian Cybele, Phoenician Astarte-Atargatis, Hellenic Demeter had all penetrated the Roman pantheon by the last centuries B.C.

With the worship of these female gods becoming more and more widespread, the Roman state intermittently attempted to Romanize the cultic practices surrounding them, and purge them of foreign elements. The main reasons for their occasional expulsion from Rome was the trance state they produced in their worshippers and (in certain cases) the high-handed behaviour of their priests, who were seen as contributing to the moral decay of Roman citizens.

Nevertheless, some emperors looked on the mystery religions with an exceptionally favourable eye, including Augustus and Hadrian, both of whom were initiated into the Eleusinian Mysteries while visiting Hellas. Claudius even tried, albeit without success, to transplant the Eleusinian Mysteries to Rome.