It is an easy thing to walk past without a second thought, yet it is likely all that remains of a fortification that once formed part of an entire medieval borough, and which fell into ruin within little more than a decade of being built.

The structure was raised by William Cary, who served as Viceroy, sometime after 1628. Cary gave his name to what was known as Carysfort, a medieval borough in this part of Wicklow, a planned settlement granted certain civic and trading rights under a formal charter. The fortification sat on a gentle south-facing slope, a practical choice for visibility and drainage. Its working life was brief. In 1641, during the uprising of the Irish Confederates, a loose alliance of Gaelic Irish and Old English Catholics who sought to reclaim Catholic and political rights, the structure was seized. After that it was simply left to decay, the stones gradually settling into the hillside. The local memory of what once stood here has survived longer than the masonry itself; the surrounding land is still known as the castle field.

For anyone visiting the graveyard at Macreddin, the wall fragment is close to St Brigid's church. It is not signposted or interpreted on site, so knowing what you are looking at requires some preparation. The remains are modest, and the setting is quiet, but the combination of the old churchyard, the stub of fortification, and the field name just beyond the boundary gives the place a layered quality that a little foreknowledge makes considerably more interesting.