But at this quiet site above Caherglassaun Lough in County Galway, that gap is one of the more interesting questions on offer. It may be the original entrance to the enclosure, the threshold through which people and animals passed in and out of a defended farmstead during the early medieval period.

The site is a rath, the most common type of monument surviving in the Irish landscape. A rath is essentially a circular or subcircular area enclosed by one or more earthen banks, typically the remains of a farmstead occupied roughly between the fifth and twelfth centuries. This particular example is well preserved, measuring just under sixteen metres in diameter, with its defining bank most intact along the western and northern arc through to the east-south-east. It sits in grassland with Caherglassaun Lough visible to the south, a relationship between enclosure and water that was common in the placement of such sites. A field boundary runs along the north-east edge, a reminder of how later agricultural organisation pressed up against, and sometimes incorporated, much older structures. The place name element "Caher" itself derives from the Irish cathair, generally used for a stone fort or enclosure, which hints at a landscape that has long been shaped by these kinds of enclosed settlements.