That tablet is long gone, but the circumstances that brought Sir Henry Roche to Mayglass, and left his monument on a church wall, are specific enough to feel almost novelistic. The parish itself takes its name from the Irish Magh glas, meaning a green plain, and its church of St Fintan sits within a rectangular graveyard enclosed by an earthen bank and hedge, the whole resting on the southern tip of a gentle north-south spur of land in the flat Wexford countryside.

The church is documented from at least 1312, when Mayglass was attached to the deanery of Ferns. By 1397 William de St. John held the rectorship, and the parish continued to generate records through the medieval and early modern periods. The most vivid episode dates to 1569, when an inquiry into the rights of the Dean of Ferns at Mayglass uncovered events from nearly a century earlier. In 1479, Laurence Neville had become Dean of Ferns and, in compensating his rival Sir Henry Roche for the position, handed him the Deanery of Ferns along with the manor and court at Mayglass. Roche apparently lived out his remaining years there, and the 1569 inquiry noted, in its own spelling, that his monument remained in the church, painted upon a tablet bearing his name and title. By 1615, when the Protestant bishop of Ferns, Thomas Ram, visited, Jacob Stafford was vicar and both church and chancel were reported to be in good repair. A few decades later, around 1680, a writer named Synnott was still listing it as the church of St Fintan at Mayglass.

What survives today is partial but architecturally layered. The building was a nave and chancel church just over 25 metres in external length. The oldest visible element is the plain Romanesque doorway, a doorway of two orders, meaning it has two concentric arched frames, set towards the western end of the south nave wall; it was repaired in 1914. The upper portion of the west gable, including a double bellcote at the apex and a two-light window with ogee-shaped heads and hollow spandrels, is a later rebuild, distinguishable by the smaller stones used above the original base. The chancel's east window, probably 15th-century work, is composed entirely of Dundry stone, a limestone quarried near Bristol that was widely imported into medieval Ireland, and retains the stumps of what was once an elaborate interlace carving, though the stonework has been robbed. Roughly 130 metres to the south lies the site of St Fintan's Well, where a pattern day, a traditional gathering of prayer and observance, was held each year on the 17th of February.