Ancient Monuments

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Llys Rhosyr

A Scheduled Monument in Rhosyr, Isle of Anglesey (Ynys Môn)

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Latitude: 53.162 / 53°9'43"N

Longitude: -4.3662 / 4°21'58"W

OS Eastings: 241905

OS Northings: 365378

OS Grid: SH419653

Mapcode National: GBR 5D.4V5B

Mapcode Global: WH435.XS19

Entry Name: Llys Rhosyr

Scheduled Date: 20 March 1997

Source: Cadw

Source ID: 14

Cadw Legacy ID: AN129

Schedule Class: Domestic

Category: Manor

Period: Medieval

County: Isle of Anglesey (Ynys Môn)

Community: Rhosyr

Traditional County: Anglesey


In 1990-91, as part of an initial survey of the llysoedd and maerdrefi of Gwynedd, GAT identified the approximate locations of several of the courts of the Welsh princes. In 1991-2 six llys sites on Anglesey were investigated and a minor assessment excavation at Rhosyr indicated the possibility of important remains in the field known as Cae Llys.

In 1993 some further assessment excavation was carried out and this indicated the need for more extensive work to establish the nature and extent of the monument. Excavation continued with Cadw support during 1994 and 1995, and at a reduced level in 1996.

The results of the excavation have yet to be fully analysed but some key features can be highlighted.

The principal structure is a very large building measuring 15m x 9m internally in its initial phase. It had a central hearth and was later extended with the addition of ranges to the east and south sides. Although robbed of much stone this was clearly a building of considerable significance and it has been interpreted as the main hall - the focal point of the Llys and the administrative centre for the area.

Immediately to the south of the hall was a rectangular cruck-built structure measuring 12m x 7m. Three entrances have been identified and a passage leads from the south side, possibly towards another building, as yet unidentified. The walls of this building survive to over 1.0m in height.

A third substantial building, also with particularly well preserved walls, has been identified to the N of the hall.

Surrounding the buildings is a well-built perimeter wall which still stands over 1.0m high in many places. Its thickness increases either side of a well-defined entrance on the east. Elsewhere the line of the wall has been traced around the south and north but the western boundary has not been identified with certainty. Altogether the Llys Rhosyr complex appears to cover at least 0.5ha.

The site has produced a wide range of artefacts consistent with its importance. Most notable is the number of coins dating form the 13th and 14the centuries.

The extraordinary preservation of these remains has been ensured by the wind blown sand which has sealed the archaeological deposits and protected the masonry features.

Source: Cadw

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