The church itself was built in the nineteenth century over the former chancel of the medieval church of St Mary's, which dates to the thirteenth century, so the building is in one sense a container within a container. The tomb is effigial, meaning it carries a carved likeness of the person it commemorates, and the figure here is a Butler knight rendered in high relief. His face, however, is not quite his own: the front part of the head was restored at some point, and as one scholar noted, the replacement does not belong to the original monument. Birds are carved into the cushion on either side of that substituted face, and at the other end the knight's feet rest on a maned animal that appears to be a lion. The upper corner of the slab is broken away, and cracks run through the stone in several directions, taking with them much of the knight's legs and portions of his sword.

Who the tomb actually commemorates is genuinely unresolved. One possibility, raised by Rae in 1970, is that it served as a cenotaph, a memorial monument separate from the place of burial, for James MacEdmond MacRichard Butler, who died in 1487 and was married to Sabhdh MacMurrough Kavanagh. The difficulty is that James is actually buried at the Augustinian friary in Callan. Rae himself leant more towards James's brother Walter, who died in 1506, reading the distinctive lion rampant on one of the Butler shields at the head of the tomb as a possible allusion to Walter's mother, Giles O'Carroll, or to the arms of his wife's family, the O'Mores of Laois. The heraldic argument works in either direction, which is part of why the question remains open. What may be more telling is the broader context of patronage: Piers Butler and his wife Margaret FitzGerald, who died in 1542, are thought to have commissioned this tomb and several others in the early sixteenth century as a deliberate effort to reinforce the MacRichard Butlers' claim to the contested Earldom of Ormond by surrounding themselves, so to speak, with commemorated ancestors.

The panels surrounding the tomb are carved with ogee-headed niches, each framed with foliate finials, and populated with a near-complete college of apostles along with Christ shown as Judge, an archbishop, and a veiled female saint. Each apostle carries his identifying attribute: St Bartholomew holds a flesher's knife, St James Major wears a scallop shell in his pilgrim's hat, St Andrew carries a saltire cross, St Peter his keys. The level of detail is considerable even where the stone is damaged, and the cracks and losses that run through several of the panels give the whole ensemble a slightly precarious quality, as though it has survived more by persistence than by protection.