They rise from fields as grassy mounds or clearly banked enclosures, their circular logic still readable in the landscape after a thousand or more years. The rath at Aughalin, in County Limerick, does something quieter and, in its way, more interesting: it has been almost entirely absorbed into the working farmland around it, ploughed and grazed into near-invisibility, yet it refuses to disappear entirely.

A rath is an early medieval enclosed settlement, typically Irish in character, usually dating from somewhere between the sixth and twelfth centuries. They were built as farmsteads, the earthen bank and surrounding ditch offering a modest degree of protection for a family and their livestock. The Aughalin example sits on a terrace cut into a steep west-facing slope, the level ground presumably making it an attractive site for whoever chose it. The enclosure itself is roughly sub-circular, with a diameter of approximately 34 metres. What survives of the original bank stands only around 0.2 metres above the interior ground level, with the outer face even lower at roughly 0.1 metres. The external fosse, a shallow ditch that would once have reinforced the enclosure, survives to a depth of about 0.25 metres and a width of 2 metres, running from the south-south-west around to the east-south-east. At some point a field boundary was cut straight through the north-east to east-south-east portion of the enclosing bank, truncating it and compounding the general erasure. The record was compiled by Denis Power and uploaded in August 2011.

Visiting a site like this requires a particular kind of attention. There is no dramatic earthwork to photograph, no obvious feature to walk towards. The sub-circular shape of the enclosure is likely to show itself best in low, raking light, especially in the early morning or late afternoon on a clear winter's day, when shadows pick out even slight changes in ground level. The site sits within what appears to be private pasture land, so any visit would require landowner permission. Once you have found your bearings on the terrace, look for the faint outline of the fosse on the southern and eastern arc, where it is best preserved, and consider the western slope falling away behind you, the same view that whoever lived here would have had when this was a place of daily life rather than a faint mark in a field.