The sarcophagus, tapering from roughly 73 centimetres at the head down to 50 centimetres at the foot and just over two metres in length, now sits in the hall of the Vicars Choral, where it has been kept since 1983. One side of it is carved with a gothic arcade in relief, the spandrels, those triangular spaces between the arches, filled with quatrefoil ornaments. The other long side is left rough and unfinished, a detail that tells you something straightforward about how it was originally installed: it was set flush against a wall, with only one face ever intended to be seen.

The coffin was discovered around 1770 in a crypt beneath the medieval Franciscan Friary that once stood on the Rock. When that friary was subsequently demolished, rather than being preserved or studied, the sarcophagus was moved to the entrance of the Catholic church built on the same site, where it was pressed into service as a holy water vessel, its interior apparently suited to the purpose by two drainage holes cut into the stone. Local tradition held that it was the burial coffin of Sir William Hackett, the reputed founder of the friary, though this connection has never been confirmed. The story takes a further twist when you consider that an effigy now standing among the monuments in the grounds of the Church of Ireland Cathedral of St. John on the Rock is believed by some to be the original lid of this same sarcophagus, the two pieces having become separated at some point in their long and complicated afterlives.