Caer Gai

Caer Gai (also Caer-gai) is a Roman fort in the district of Penllyn, Gwynedd, Wales,. It is located about 1 mile or 1.6 km north of the village of Llanuwchllyn, and the same distance west of Lake Bala;.

The locality
The River Dee runs past the foot of the hill on which the fort stands. Behind the fort, to the north, rise mountains culminating in Arenig Fawr (854 metres or 2802 feet); while in front of it are the Berwyn Mountains and Aran Benllyn. The Roman road from Chester to Brithdir (on Sarn Helen) runs past the fort. Another Roman road connects the fort with the Roman fort of Tomen y Mur, through Pennant-Lliw.

The fort lies on a low shoulder with steep slopes on three sides. It encloses about 4 acres (1.6 hectares) of land. The remains of the external wall can be seen in places, with five courses of stonework. The mansion of Caer Gai (the present building dates from the 17th century) conceals part of the Roman fort. There is a ford on the Roman road near the fort.

Roman fort
The first fort, constructed of wood and earth, is believed to have been constructed at the time of Emperor Titus. A stonework fort was built there around AD 100. A fragment of a statue was discovered with a Latin inscription recording that it was made by Julius, son of Gavero, a soldier in the 1st Cohort of the Nervii: ('IVLIVS GAVERONIS F(ilius) FE(cit) MIL(es) CHO(cohortis) I(primae) NER(vium)'. The statue stood in a sanctuary 100 metres to the east of the fort; shards of pottery were also found there dating from around the first half of the 2nd century (AD).

A Roman tomb connected with the fort was found 400 metres to the north-east. It is assumed that there was a small settlement next to the fort. Traces of a building, probably a bath house, were discovered to the south-east.

The fort is named after the legendary hero Cai, son of Cynyr (Sir Kay), who appears in the tales of King Arthur, including Culhwch and Olwen and the Three Welsh Romances. The fort is referred to as Cai's home in the work of the Bards of the Nobility (Beirdd yr Uchelwyr).

Late Middle Ages
The fort was the home of the bard Tudur Penllyn (c. 1420-1485) and his son Ieuan (fl. c. 1480). Tudur obtained the fort after marrying Gwerful Fychan, a descendant of Rhirid the Wolf (died c. 1160), and the fort may have been owned by Rhirid when he received the lordship of Penllyn. There are references to the court of Penllyn being held at the fort in medieval times, before it moved to Bala.

17th century
A new mansion was later built on the site. Rowland Vaughan (c. 1587-1667), a poet and well-known royalist in the English Civil War, lived there. The mansion was burnt down in 1645 during that war, but a notable farmhouse was built in its place, which is still standing today.

The site is in the care of CADW and is open to the public. It is registered with the number ME018.