Ancient Monuments

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Caer Gai Roman Site

A Scheduled Monument in Llanuwchllyn, Gwynedd

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Latitude: 52.8689 / 52°52'7"N

Longitude: -3.6684 / 3°40'6"W

OS Eastings: 287793

OS Northings: 331460

OS Grid: SH877314

Mapcode National: GBR 69.R9DQ

Mapcode Global: WH67B.M4CZ

Entry Name: Caer Gai Roman Site

Scheduled Date:

Source: Cadw

Source ID: 284

Cadw Legacy ID: ME018

Schedule Class: Defence

Category: Fort

Period: Roman

County: Gwynedd

Community: Llanuwchllyn

Traditional County: Merionethshire


The monument comprises a Roman fort, together with roads, annexe and vicus at Caer Gai. The site is located on a spur overlooking the River Dee to the S. The primary Roman fort network was designed and constructed by the Roman army for the purpose of military conquest and rule. This fort was part of a network of forts occupied to protect routes across north Wales from the Flavian period of conquest (AD 74) until the mid-second century. The monument survives primarily as buried features, except for the fort, which is clearly visible as a rectangular earthwork. A programme of geophysical survey and trial trenching between 2000 and 2006 refined current understanding of the extent and character of the fort's environs. An annexe, containing two buildings interpreted to be a mansio, or official inn, and a bathhouse, is located to the SE of the fort. A probable second annexe is located to the SW of the fort. The vicus, a non-planned civilian roadside settlement, is located immediately NE of the fort.

The monument is of national importance for its potential to enhance our knowledge of Roman military organisation. The monument forms an important element within the wider context of the Roman occupation of Wales and the structures have been demonstrated, through excavation, to contain well preserved archaeological evidence concerning chronology, layout and building techniques.

The area scheduled comprises the remains described and an area around within which related evidence may be expected to survive. It is an irregular polygon in shape and measures c. 400m NE-SW by 350m transversely.

Source: Cadw

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