The placename Castlegannon combines the English word for a fortified residence with a Gaelic personal name, suggesting a locale where ecclesiastical and secular power once occupied the same ground. That kind of overlap is not unusual in the Irish midlands and south-east, where early medieval monasteries and later Norman manorial centres frequently grew up in close proximity, each leaving traces that can be difficult to unpick without careful fieldwork.

Beyond its name and its recorded existence as a monument, the specific history of this church, its founding, its patron, its architectural form, and the community it served, remains to be fully documented in the public record. What can be said is that Kilkenny as a county contains an unusually dense concentration of early Christian and medieval ecclesiastical sites, a reflection of the region's importance under both the Gaelic lordships and the Anglo-Norman settlers who transformed so much of Leinster from the twelfth century onward. Whether this particular site belongs to the earlier Gaelic period or to the wave of parish church construction that followed the Norman settlement is a question the archaeology of the place itself would need to answer.