Set into the ground at the foot of stone steps descending along the outer face of the south transept wall, the slab seals the entrance to a subterranean burial vault, positioned so that the stone itself becomes a threshold, a door of sorts, between the living world and the family chamber beneath.

The slab dates to 1679 and was commissioned by Walter Pollard, whose family gave their name to the town. The inscription, preserved in full, records that Walter erected the monument for the interment of himself and his wife Elizabeth, described as the only daughter of Arthur Dillon of County Westmeath, Esquire, and for those of his name and family. The careful phrasing suggests a man thinking ahead, reserving space not just for two people but for a lineage. The top of the slab carries the Pollard family's armorial shield, and below the inscription, at the base of the stone, the motto Memento Mori appears alongside a skull and crossbones. That phrase, Latin for "remember that you must die", was a standard piece of funerary rhetoric in this period, though carved here in combination with heraldry and a family dedication, it takes on a particular weight. The vault beneath the south transept chapel of Castlepollard church was not incidental to the building; it was a deliberate piece of family architecture, placing the Pollards physically within the fabric of the church, generation after generation.