mithraism

from WordNet (r) 3.0 (2006)

Mithraism
    n 1: ancient Persian religion; popular among Romans during first
         three centuries a.d. [syn: {Mithraism}, {Mithraicism}]

from The Collaborative International Dictionary of English v.0.48

Mithraism \Mithraism\ prop. n.
   The ancient Persian religion which worshiped Mithra; it was
   popular among Romans during first three centuries a. d.

   Syn: Mithraicism.
        [WordNet 1.5]