Last week, I mentioned that the Roman religion that developed in Britain was different from what was practiced in Rome itself. This was true of the Britons, but it was also true in regard to the beliefs of the legionaries who served in Britain, mainly through their worship of the god, Mithras.

Mithras, who was a god of friendship, contract, and order, started out as an Indo-Iranian deity, and once Rome conquered Iran, spread very quickly throughout the Roman Empire. Mithraism is described by scholars as a ‘mystery’ cult because worship of Mithras was secretive and involved seven degrees of initiation, each of which required the initiate to perform a task.

The cult was so secretive, in fact, that few written records of the Mithras cult have survived, and virtually everything we know about it comes from carvings and statues. These generally depict three events: the birth of Mithras from a rock, Mithras slaughtering a bull, and him dining with Sol, the sun god, on the slaughtered bull’s hide.

The Roman legions brought the Mithras cult to Britain, and remains of ten temples dedicated to Mithras have been discovered. Generally, they were all constructed similarly, in that they have a sanctuary, a long narrow nave, and an outer room. Though the ideal within the cult, and in keeping with secrecy, was to build underground, even in a cave, many temples to Mithras in Britain were not constructed that way. While the most famous temple and best preserved temple to Mithras in Britain is in London, three have been discovered along Hadrian’s Wall. The one we visited was at Carrawburgh.

Carrawburgh Roman Fort is one of 16 forts along the 73-mile long Hadrian’s Wall, which was begun around AD 122 and housed a garrison of approximately 500 soldiers. As I talked about last week—and actually in videos last season about the Roman conquest of Britain, these soldiers were not from Rome. The first legion came from south-west France, and it was later replaced by a legion from Belgium. The temple to Mithras here was probably built by soldiers at the fort around AD 200 and destroyed about AD 350. It had three altars, each dedicated by commanding officers of the First Cohort of Batavians, so commanding this second legion from Belgium.

Another military site with a Mithras temple was Segontium—Caernarfon. It actually plays a role in Crouchback, the first book in the Welsh Guard Mysteries. Unfortunately, it can’t be visited because, after excavation, it was covered over with houses.

Interestingly, at one time, the cult of Mithras was seen by Romans as a rival to Christianity, but once Christianity became the official religion of the Roman Empire, the Mithras cult faded, even among the legions. And it’s early Christianity in Britain we’ll be talking about next week.