Mithra was worshipped throughout the
Roman era, from the
late Republic to the
later Imperial era. The cult of
Mithraism spread from the
Middle East to other parts of the
Roman Empire throughout the
Mediterranean basin, at first by military-political adventurers, travelers, slaves and merchants from the
Orient. Later, Mithraism was spread by
soldiers whose legions came into
contact with the followers of the
cult in the East. The temple dates back to the early 4th century, although it could be as ancient as the 2nd century with repairs undertaken during the early 4th century. This particular Mithraeum is one of the best-preserved sites in Europe. The Jajce site is a typical
spelaea.
Mithraism followers typically sought to set up their places of worship in caves. In the absence of such topographical features, they excavated the soil and built the small single-celled temple (
spelaea) to reinforce the impression of a cave. ==Discovery and protection==