The rath at Rochestown in County Wexford offers none of that. It survives only as a cropmark, a faint circular shadow pressed into the soil of a level field, legible not to the eye on the ground but to a camera carried overhead.

A ringfort, or rath, was a roughly circular enclosure defined by an earthen bank and an outer ditch, used as a farmstead and dwelling place during the early medieval period, broadly the fifth to twelfth centuries. Thousands survive across Ireland in varying states of preservation. The Rochestown example measures approximately twenty-five metres in diameter and is defined by a single fosse, the term for a defensive or enclosing ditch cut into the ground. What marks it out is the manner of its survival. Aerial photographs reveal the circular outline of that fosse as a cropmark, a phenomenon that occurs when buried features affect how plants above them grow, producing differences in crop colour or height that become visible from above. The enclosure was identified on aerial photographs held in the national collection, and remained faintly discernible in the Ordnance Survey Ireland aerial series as recently as 2005.