The inscription names William Sweetman, Baron of Erley, who died in 1507, and his wife Johanna Tobyn, and asks that God have mercy on their souls. That it survived at all is something of an accident: the slab lay buried or obscured for centuries before a graveyard clean-up between 1985 and 1987 brought it back into view.

The slab measures 1.92 metres long and 0.73 metres wide, and its surface carries more than just words. Running down the centre is a raised floriated cross, the kind with decorative leafy terminals common in late medieval Irish stonework, and beside it a heraldic shield bearing the Sweetman family arms: ermine ground with a fesse and, in the lower section, a chevron. The arms are described precisely in an 1905 account by Carrigan, who recorded the inscription in full before the slab had attracted much further attention. The Old English lettering uses the contracted Latin formulae standard for memorial slabs of the period, compressed into abbreviations that scribes and stonemasons both understood. William's title, Baron of Erley, ties him to the Newtown Earley estate, and Johanna Tobyn's surname connects the slab to one of the other prominent Anglo-Norman families then settled across south Kilkenny and Tipperary. The slab now rests inside the shell of the medieval church itself, sheltered from further weathering.