Measuring roughly 65 by 57 centimetres, it is not especially large, and its position within the fabric of the wall suggests it was incorporated deliberately rather than left as an afterthought. An armorial plaque of this kind would have displayed a family's coat of arms, serving as a public statement of identity, patronage, and claim to prestige, the kind of thing a powerful Connacht family might commission to assert their connection to a sacred or significant site.

The O'Kellys were one of the great Gaelic dynasties of Connacht, with deep roots across counties Galway and Roscommon, and their association with ecclesiastical sites was longstanding. The plaque is thought to date from the 18th century, which places it in a period when Gaelic families were navigating the pressures of the Penal era, when the open expression of Catholic identity carried real legal risk. That a family would mark their presence inside a friary wall during such a period is quietly telling. The Dominican friary at Tulsk itself has medieval origins, and the survival of this later addition within its fabric points to the layered way in which such buildings accumulated meaning across generations.