Tradition holds that the chapel was built in fulfilment of a vow made by a shipwrecked person - the kind of bargain made in extremity, brought to land when the survivor was unexpectedly delivered alive. The chapel was originally dedicated to Ninian, the fourth-century Pictish saint associated with Whithorn in Galloway, just across the Solway from the Manx coast. Over time the name softened into Trinian. The site is older than the dedication, though: a seventh-century cross on a grave in front of the altar proves earlier Christian use here. What stands today is recorded as a fourteenth-century church, but it was built on consecrated ground that had been holy for at least seven hundred years before. The Barony of St Trinian's once consisted of a religious house, a set of hospitals or guest houses, and the church itself - tenants here owing fealty to a Baron who was himself the King of Mann's vassal. For a structure now roofless and half-forgotten, it sat in a thicker web of obligation than the open fields around it suggest.

The folk tale's hero is a Manx tailor named Timothy. He wagered that he could sit alone in the church through a single night and stitch a pair of breeches before the Buggane finished tearing off the new roof. Tailors were often the heroes of these tales - quick fingers, quiet patience, a useful indifference to interruption. The Buggane rose from the ground inside the chapel and began taunting him. Timothy did not look up. He stitched. The Buggane's threats grew louder. Timothy stitched faster. He finished the last seam just as the roof crashed in, leapt out the door with his needle and scissors clattering behind him, and ran. The Buggane chased him across the field, jaws extending like a creature out of nightmare, and Timothy hurled himself onto consecrated ground - the only place a Buggane could not follow. In a fit of fury the ogre tore off its own head and threw it after him, where it exploded like a bomb. Timothy was unscathed. The roof was gone forever.

The Reverend Philip Moore was born in 1705 and spent nearly forty-eight years as chaplain of Douglas, preaching at Bishop Wilson's funeral and serving as curate of Marown - the very parish in which St Trinian's stands. Moore took a dim view of country folk believing in ogres. One night he set out to cure them of it by climbing onto the ruins and masquerading as the Buggane himself, presumably hoping a frightened parishioner would later see through the trick and feel foolish. The plan got him into Bishop Wilson's bad books - the historical record does not say whether he succeeded in talking anyone out of the folklore. What the episode does record is how deeply the tale was woven into local belief by the eighteenth century: serious enough to draw a clergyman into a costume on the ruins, and stubborn enough to outlast both the clergyman and the lesson he was trying to teach. The story is still told. The roof is still gone.

On 25 May 1908, Manx National Heritage became the guardian of St Trinian's as a Scheduled Ancient Monument, taking responsibility for both the ruined chapel and its former burial ground. The deed was filed under Mar.1909.00108. Public access was formally guaranteed by a later deed on 17 July 1982, with a stipulation that has the rare charm of being read straight from a legal document: People, but not dogs, should have unrestricted access to St. Trinians Chapel through the wicket gate. The gate is still there. The chapel is still roofless. Greeba Mountain still rises behind it. And if you stand inside the open ruin on a windy day, with the A1 just audible through the hedgerow and the grass growing where the floor used to be, the story about the Buggane feels less like an explanation and more like a small Manx joke about anything that refuses to be finished.