Sarn Helen means “Helen’s Causeway.” It is named for Elen, the wife of Macsen Wledig, who Welsh legend says ordered the building of the roads in Wales in the fourth century. The historical record indicates the road was actually built far earlier by the Roman legions who conquered Wales in the first century AD, in order to allow the rapid movement of troops and military supplies. Most of the Roman road network in Britain was completed by 180 AD.

Sarn Helen began in north Wales at the Roman fort of Cae-rhun. It ran south to Trefriw. From there it went to Caer Llugwy and Dolwyddelan. Then it headed through the Cwm Penamnen Valley. It ran past Bryn Y Castell to the fort of Tomen y Mur. From there it went to Dolgellau and may have crossed the Afon Dyfi at the Roman fort of Cefn Caer in Southern Gwynedd. At that point, it went south to Ceredigion. Part of the B road at Bronant is clearly Roman, as is a stretch through Llanio at the Roman fort of Bremia. The road passed the Dolaucothi gold mines, near the Roman fort at Leuntinum before ending in Llandovery at the fort of Alabum. All told, Sarn Helen was roughly 160 miles long.

While the Romans preferred to build straight, wide roads, as evidenced by the remains of Sarn Helen, they were often stymied by the mountains of Wales. Sometimes they merely improved older, native roads, as in the case of Bwlch y Ddeufaen in Gwynedd. In general, after surveying the proposed path, the base of the roadbed was dug three feet down and twenty feet across. It was then filled with large gravel and sand for the foundation. A layer of smaller gravel came next. Then the sides were lined with blocks, and five-sided, hand-carved stones were fitted together to make the top layer of the road. The roads were also sloped from the center so rainwater would drain off into ditches at the sides.

With the departure of the Romans, many of their forts were occupied and their roads continued to be used by the native Welsh. In other cases, the sites were entirely abandoned, leading to the decay of the road system. As time went on, the weak point in the network became river crossings because the native Britons didn’t have the technology to repair the fords and bridges. At that point, roads developed that diverted from the original course. Then, as the population of Britain grew, new roads were built that connected medieval towns.

Still, archaeologists have estimated that even in 1066, when William I conquered Britain, his armies could travel on at least 10,000 miles of usable Roman roads. Today, the Ordnance Survey maps of Britain show 2000 miles of roads.

Although much of the Roman road of Sarn Helen has been entirely lost, visible stretches remain, often through the more remote areas of Wales. If, like me, you are excited about walking in the footsteps of people who lived two thousand years ago, the Roman road of Sarn Helen is definitely worth a visit.