It was not lost by accident. This tapered effigial slab, a type of funerary monument carved to mark and sometimes depict the body of the deceased beneath, ended up in the river because someone, almost certainly in the 1540s, put it there deliberately.

The slab was one of five partial funerary monuments recovered during archaeological excavations carried out in 2001 as part of the River Nore Drainage Scheme, in the area immediately north of the current John's Bridge in Kilkenny City. The excavation, directed by N. Brady, found the fragments associated with a late medieval bridge on the same site. Brady proposed that the monuments had been deliberately defaced and thrown into the river by iconoclasts during the Reformation, when the destruction of devotional imagery and funerary ornament was carried out with considerable force across Ireland and Britain. A second interpretation, put forward by Doyle and O'Meara, is more pragmatic and perhaps more unsettling in its ordinariness: that the slabs were simply seen as a convenient source of rubble, broken up and reused as part of the protective stone apron laid around the bridge piers to guard against erosion. The two explanations are not mutually exclusive. The nearest ecclesiastical sites are St Mary's parish church, roughly 100 metres to the west, and St John's Priory, about 200 metres to the north-east, either of which could plausibly have been the original home of these monuments.

The slab itself measures 1.62 metres in length, 0.58 metres wide, and 0.15 metres thick. It survives in four large fragments, plus a fifth broken into six further pieces. The head and foot of the slab are gone entirely. A rounded edge and groove run along both long sides, and the stone tapers from head to foot in the manner typical of the form. Whether any carved effigy ever appeared on its surface cannot now be determined. Stylistically, it belongs to the 13th or 14th century. It is currently held in storage with the National Museum of Ireland, an object that outlasted the hands that tried to erase it, even if what those hands were trying to erase is no longer legible.