Most medieval church ruins contain a window or two, perhaps a worn doorway, maybe the ghost of a font. The ruined parish church at Seskinan in County Waterford contains all of those things, but it also contains something far older built directly into the fabric of the building itself: the lintels spanning the windows and doorways are ogham stones, early medieval monuments incised with an alphabet of notched lines used in Ireland roughly from the fourth to the seventh centuries. Six of the lintels carry these inscriptions, and a seventh ogham stone lies loose on the floor inside. The stones were not carved for this church. They were already ancient when the building went up, reused as convenient dressed slabs of the right size and shape, their original commemorative purpose quietly absorbed into later masonry.

The church stands on level ground at the northern edge of a rectangular graveyard enclosed by an earth and stone bank, and it sits on the site of an even earlier church. When a visitation was carried out in 1588, the building was already derelict, which places its working life somewhere in the medieval period. It is a plain, undifferentiated structure, roughly 22 metres long and just over 7 metres wide internally, with its long walls still standing to between about 2.1 and 2.5 metres. The west gable retains a damaged double bellcote and a pair of ogee-headed windows set one above the other. There are pointed doorways in both the north and south walls, a stoup just inside the south doorway, and a small aumbry, a wall recess used to store sacred vessels, at the east end of the south wall. The square base of a font remains in the church, and about 250 metres to the west lies the site of Toberatemple Well. The ogham inscriptions were recorded and read by the scholar R. A. S. Macalister in his 1945 Corpus inscriptionum insularum Celticarum; his readings include partial names and lineage formulae, among them VORTIGURN and CORB, as well as more fragmentary traces. An eighth stone, once noted by G. Redmond in 1885 and read by Macalister as commemorating MONEDIAS son of MUIBITI, was at some point removed to a house near Cappoquin and is now lost.