Ancient Monuments

History on the Ground

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Din Sylwy

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

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Latitude: 53.3109 / 53°18'39"N

Longitude: -4.1231 / 4°7'22"W

OS Eastings: 258648

OS Northings: 381426

OS Grid: SH586814

Mapcode National: GBR JM6Y.D43

Mapcode Global: WH53V.M1VN

Entry Name: Din Sylwy

Scheduled Date:

Source: Cadw

Source ID: 2514

Cadw Legacy ID: AN024

Schedule Class: Defence

Category: Hillfort

Period: Prehistoric

County: Isle of Anglesey (Ynys Môn)

Community: Llanddona

Traditional County: Anglesey


The monument comprises the remains of a hillfort situated on top of a flat-topped, steep-sided limestone hill, it probably dates to the Iron Age period (c. 800 BC - AD 74, the Roman conquest of Wales). Hillforts are usually located on hilltops and surrounded by a single or multiple earthworks of massive proportions. Hillforts must have formed symbols of power within the landscape, while their function may have had as much to do with ostentation and display as defence.

It is defended by a single stone wall which encloses an area of 7.5 ha. The enclosure wall is generally just under 2.5 m thick, and is made up of two faces of upright limestone slabs, with rubble infill. There are two certain entrances, one in the S wall and one in the W wall. The S entrance is the more imposing, being 4.5 m wide and approached by a terraced trackway, the latter being largely obscured by thorn scrub. The W entrance is between 2 and 3 m wide and is approached by a narrow path. The wall around the SW part of the fort is somewhat overgrown, but the base of the early defensive wall would appear to be surmounted by a modern field wall. The E side of the fort is very overgrown, but the OS map shows a simple field wall on the line of the defences. The NE side of the fort has been partly quarried away to serve a lime-kiln which is situated on the slopes below.

The monument is of national importance for its potential to enhance our knowledge of later prehistoric defensive organisation and settlement. The site forms an important element within the wider later prehistoric context and within the surrounding landscape. The site is well preserved and retains considerable archaeological potential. There is a strong probability of the presence of evidence relating to chronology, building techniques and functional detail.

The scheduled area comprises the remains described and an area around them within which related evidence may be expected to survive.

Source: Cadw

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