Harryville Case Study

Harryville Motte and Bailey, Ballymena, Co Antrim:
Conservation Works to an Earthwork Monument

Harryville motte and bailey is a State Care monument located on a prominent ridge of land overlooking the River Braid in Ballymena, County Antrim. Motte and baileys are a type of early castle where a raised mound or ‘motte’ was topped with a wooden or stone structure known as a keep. The earth for the mound was thrown up from a ditch around the motte. An enclosed courtyard or ‘bailey’ was overlooked by the motte. In Northern Ireland, this monument type tends to date to the time of the establishment of the Anglo-Norman Earldom of Ulster in the late 12^th and early 13^th centuries.

Harryville, like many earthwork monuments in urban areas, is used as an informal recreation space. Unfortunately, over time, some activities such as the use of bicycles on the slopes of the monument, had led to the development of deep erosion scars, particularly on the motte. These exposed erosion scars left the monument vulnerable to further erosion and weathering.

Artificial earthen ‘causeways’ had also been constructed across the surrounding defensive ditch. NIEA: Built Heritage undertook a laser scan survey of the monument which clearly shows areas of erosion and the modern ‘causeways’.

NIEA: Built Heritage has recently undertaken a programme of conservation works to help address the wear and tear to the earthwork. These works largely focused on the motte itself and involved repairing and consolidating the large erosion scars.

The soil from the modern ‘causeways’ was composed of the eroded material from the motte. This soil was carefully removed under archaeological supervision for later use to patch up the erosion scars on the motte.Timber revetments were used to help stabilise the newly replaced soil on the steep sides of the motte. These revetments were buried within the repaired areas resulting in no visible trace of this repair. On the surface of the repaired areas a special membrane was used to hold this soil in place and to help grass and vegetation to re-establish and secure the exposed areas of bare earth.

The monument had several mature trees and young saplings and bushes growing upon it. These trees posed the risk of damaging the monument if they were blown over in high winds. The shade resulting from the low-growing shrubs and saplings had caused areas of bare earth to develop which were vulnerable to erosion. As part of the conservation works, the trees and saplings were removed to prevent future damage to the monument.

NIEA’s conservation works have helped to re-establish Harryville as a prominent landmark on the local skyline. The conserved areas of the motte are in the process of ‘healing’ and will blend in with the rest of the monument when grass re-establishes and consolidates the ground surface.