The tablet is modest in every physical sense, measuring just 34 centimetres wide and 26 centimetres high, and its setting makes it easy to overlook entirely. A lancet window is the tall, narrow, pointed-arch opening common in medieval ecclesiastical architecture, and when this one was partially filled in, the memorial was absorbed into the infill rather than relocated or removed. The result is a monument that has become, almost by accident, a kind of archaeological sandwich, caught between the original medieval fabric and whatever intervention closed the window.

The inscription, rendered in the orthography of its time, reads: "PRAY FOR THE SOVLE OF MATHEW SEMPER WHOSE SOVLE YE LORD RECEAVE 1670." The spelling of "soul" as "sovle" and the use of "ye" for "the" reflect seventeenth-century conventions rather than illiteracy; "ye" in this context is simply a typographic carry-over from the older thorn character. Beyond the date of 1670 and the name Mathew Semper, the tablet offers no further biography, no indication of rank or family, no heraldic device. The monument was recorded by R.A.S. Macalister in 1913, and the combination of its location within a pre-existing architectural feature and the plainness of its commemoration gives it a quietly specific character, a single name lodged in a wall that had already been standing for centuries before 1670.