Caernarfon Mithraeum facts for kids

The Caernarfon Mithraeum was a special Roman temple dedicated to the Roman god Mithras. It was found near the old Roman fort of Segontium, which is now part of Caernarfon in Gwynedd, Wales.

This ancient temple was discovered by accident on April 2, 1958. The National Museum of Wales then dug up the site in August 1959. George Boon led this important work. They found that a sewer trench had already damaged part of the temple. The ground was also very marshy, suggesting a stream once flowed nearby. This made the digging difficult, but most of the temple could still be explored.

What is a Mithraeum?

A Mithraeum is a special kind of Roman temple built for followers of the god Mithras. These temples were usually built partly underground or designed to feel like a cave. They often had a long, narrow main room called a nave. This nave was usually sunken, with raised benches on either side. People would sit or recline on these benches during ceremonies. At one end of the temple, there was usually a special alcove. This alcove held a statue or painting of Mithras slaying a bull, which is called a tauroctony.

Discovering the Caernarfon Mithraeum

The Caernarfon Mithraeum was found by chance in 1958. It was located about 137 meters northeast of the Roman fort of Segontium. When archaeologists started digging, they faced some challenges. A modern sewer line had cut through the temple's entrance area. The ground was also very wet and marshy. This suggested that a stream might have flowed close to the temple long ago. Despite these difficulties, most of the temple was successfully uncovered.

Building the First Temple: Phase I

The first version of the Caernarfon Mithraeum was built around the 3rd century AD. At this time, the Roman fort nearby was home to a group of soldiers called the Cohors I Sunicorum. The temple was built at the bottom of a small valley. It measured about 14.6 meters long and 6.55 meters wide.

The temple had an entrance room, called a narthex, at its southern end. After this, you would enter the main temple area. This main area had a sunken central floor, or nave. On either side of the nave were low benches. This design is very typical for Mithraic temples. At the northern end, there was a rectangular alcove. This is where the important tauroctony image of Mithras would have been placed. The walls were made from rough beach boulders, giving the temple a rustic look. Pieces of purple slate tiles were found, showing what the roof was made of. A very old coin from Faustina I (138-139 AD) was found. This coin helped archaeologists guess when the temple was built.

Changes to the Temple: Phase II

Not long after the first temple was built, some changes were made. This was called Phase II. Wooden colonnades (rows of columns) were added inside. These columns probably helped to hold up the heavy slate roof. The columns stood on small stone bases. Interestingly, each base was different. Some were square, and one was round. This suggests they were reused from other buildings.

A special V-shaped drain, lined with tiles, was also added to the floor. This drain brought spring water into the temple. It ran diagonally across the main room and ended near the northern bench. A tank must have been there to collect the water. Archaeologists believe this phase happened very soon after the first one.

The Final Temple: Phase III

The third and final phase of the temple happened after part of the roof collapsed. Broken slate tiles were used to raise the level of the main floor. This might have been done to stop the temple from getting waterlogged, which could have been a problem in earlier phases. A new cobbled floor was then laid down.

To match the higher floor, the benches and the area in front of the alcove were also raised. Small sets of two steps were added to help people get onto the benches. More steps led up to the alcove area. A stone platform was also built to the right of the alcove. This platform might have been a base for a statue. The wooden columns from Phase II were removed. Instead, at least five small pedestals were placed along the front of the benches.

Archaeologists found a thin layer of soil on top of the Phase III floor. Above this soil was a layer of burnt debris. This suggests that the temple was left empty for a while before its roof burned down. It also explains why no Mithraic statues were found inside. They were probably removed when the Roman soldiers left Segontium around 290 AD.