People once came to it before dawn, carrying water from a nearby well, to say rosaries and wash their eyes in hope of a cure. They left rags or small tokens on a tree beside it, and local belief held that anyone who touched one of those rags would contract whatever disease the original petitioner had brought to the stone. The stone is known as Cloch Mochaeda, the stone of St Carthage Mochaeda, and it sits on the footpath leading to what was once the Rectory.

The church that now occupies this site is a Board of First Fruits building, the body responsible for funding Church of Ireland construction in the early nineteenth century, dating from 1816. It has a three-bay nave and a three-stage entrance tower to the west, and was renovated and extended around 1875. But the ground beneath it carries a much longer religious history. The place-name Kiltallagh derives from Cill Tulach, meaning the church of the hill, and the site was associated with St Carthach Mochuda, an early Irish saint of some significance. O'Donoghue, writing in 1893, suggested this may have been the church from which Carthage Mochuda was forced to withdraw, and which a Bishop Domaingen subsequently gave into the care of his brother Faolan. By 1302, the church appeared in a papal taxation of the Deanery of Offeria in the diocese of Ardfert, valued at 13 shillings and 4 pence annually, with the tithe set at 16 pence. In 1871, a writer named Cusack noted that the medieval church had stood precisely where the Protestant church then stood, with scattered stones from the earlier structure still visible around the graveyard.

The folkloric life of the site persisted well into the twentieth century. Children from Castlemaine School recorded traditions about the old church ruin, including accounts of a great light seen there on dark winter nights, three priests said to be buried within the ruin, and the ruined settlement of Clounalassan nearby, thought to have been connected to the father of Fingen Macuda. The healing rituals at the Cloch Mochaeda, performed before sunrise with well water and rosary prayers, point to a layering of Christian and older devotional practice that was once common at such stones across Ireland. The stone itself, hollowed and worn, remains among the grave markers and mausolea of the 1816 churchyard, easy to overlook without knowing what it is.