Yet that is precisely what this slab beside St Patrick's Cathedral amounts to: a medieval funerary stone, carefully decorated, that was quietly repurposed by 17th-century engineers and only recovered in 1901 when workers excavating Dublin's main drainage system broke into the north wall of an old stone culvert carrying a branch of the River Poddle.

The slab was found at the west end of the cathedral, and the culvert it had been built into dated from around the 17th century, constructed to manage the Poddle, one of Dublin's subterranean rivers that once fed the city's moat and mill ponds. Whoever built the culvert showed little sentiment about the stone's original purpose, slotting it into the wall as a convenient flat-faced block. The slab itself is granite, measuring roughly 1.14 metres long and just over half a metre wide. Its decoration is detailed and deliberate. A Greek cross, the kind with four arms of equal length, is rendered in raised outline within a double raised ring, with a small round boss at its centre. Below this sits a Latin cross in low relief, the longer-armed variety more familiar from Christian iconography, with large circular hollows carved into the angles between the arms. A round moulding runs along both edges of the slab and curves inward at the top, forming a pair of hooks that frame the ringed cross above. The combination of motifs, the ringed cross especially, suggests early medieval Christian carving traditions, though the notes do not give a precise date.

The slab is associated with St Patrick's Cathedral, which occupies the south-western part of Dublin city, a short walk from the old city walls. The cathedral grounds and the immediate surroundings along the Poddle's historic course repay attention from anyone interested in the layered infrastructure beneath the city as much as the architecture above it. The recorded location is the west end of the cathedral. For anyone following up the specific object, the reference in the notes is Swords, K. (ed.), 2009, which suggests it has been catalogued in a survey context rather than put prominently on display, so it is worth contacting the cathedral or the relevant heritage body in advance to establish where exactly it can be seen.