The church known as Kilbixy, or Ceall Bhigsighe, was dedicated to St. Bigseach, a figure connected to St. Brigid and commemorated on the 28th of June. Seventeenth-century sources identify her as the daughter of Breasal of the Uí Fhiachrach, a Connacht tribe, which places the original foundation in an early medieval context that long predated the parish boundaries drawn around it.

The church was already old when the Normans arrived. A charter dated somewhere between 1192 and 1218 records Geoffrey de Costentin granting it to Ralph Petit, archdeacon of Meath, though the building was established before the Norman settlement. It passed shortly afterwards to the Augustinian canons of Tristernagh Priory, located 1.9 kilometres to the south-east, and the connection with that house persisted for centuries; the church is mentioned in records from 1259, 1492, and 1540. By 1682, the antiquarian Piers described it as "the remains of an ancient and well built church, the mother of many churches and chapels about it," still retaining a high tower at its western end. The 1656 Down Survey map confirms this, depicting the building as a fortified structure with a battlemented tower, a form seen at comparable Westmeath churches at Taghmon and Kilpatrick. None of that medieval fabric survives above ground today. The ruins visible now belong to a Church of Ireland building constructed around 1800, almost certainly on the same footprint. When the scholar John O'Donovan visited in 1837, he catalogued what remained: a ruined leper house, no trace of the castle walls, a moat surrounded by a circular fosse, the site of a gallows, and a holy well dedicated to St. Bigseach.

A few physical details reward a careful look. The semi-circular ditch north-east of the church is not medieval at all but a post-medieval landscape feature, a decorative fosse associated with the eighteenth-century church building, whose construction was noted in the 1793 edition of Anthologia Hibernica. Near the church stands an octagonal limestone font, and a chamfered limestone fragment from a medieval arch has been repurposed as a grave-marker, its carved edge worn but still legible to anyone who pauses over it.