The inscription reads 'ANOD 1610', which is a contracted form of Anno Domini, placing the carving firmly in the early seventeenth century. Above or around it sit two capital letter H's, and beneath them what has been interpreted as a possible Freemason symbol. That last detail is the puzzling part. Organised Freemasonry as most people understand it did not take institutional form until the early eighteenth century, which means either the identification of the symbol is mistaken, or the stone preserves evidence of an older tradition of craft symbolism that predates the lodge system.

The tower house to which the plaque belongs is a structure typical of late medieval Ireland, a fortified residence built for a local lord or landowning family, usually several storeys high with thick stone walls. By 1610, many such towers in Leinster were being adapted or added to by new English settlers, and commemorative or armorial stones were sometimes set into walls to mark ownership or building work. The two H's most likely represent the initials of a person or family responsible for some work on the structure at that time, though no name is recorded to confirm this. The plaque sits on the south-western side of the western wall, set into the fabric of the building rather than displayed separately, which suggests it was intended as a permanent marker of some significance rather than a portable object.