The name puzzles modern Gaelic speakers. Folk etymology says Inchaffray comes from innis abh reidh, the island of the smooth water, which sounds plausible until you find the earliest Latin form: Insula missarum, the island of the masses. In Gaelic the mass is oifrend, in Welsh offeren. The name actually means the island of the offerings. Before drainage, the abbey stood on rising ground that was a true island most of the year, ringed by marsh and pools thick with eels. A community of clerics called the brethren of St John of Strathearn had been here since the 1190s, drawn perhaps by the same isolation that earlier hermits sought. In 1200 Gilbert, Earl of Strathearn, and his wife Maud d'Aubigny upgraded the existing community into a priory in memory of their first-born son Gilchrist, who had been buried there in 1198. By 1221 it was a full abbey, and Inchaffray began its rise.

In 1275, the Scottish church was assessed for a crusading tithe. Inchaffray's annual income came in at 246 pounds, fourth among all Augustinian houses in Scotland, exceeded only by St Andrews, Scone, and Holyrood. The abbey's lands and dependent churches reached across the country, from Uist in the west to Balfron in the south. To improve its marshland holdings, the monks ordered the digging of the Pow of Inchaffray, a nine-mile drainage ditch that still carries water out of the basin today. Then the slow decline came. By 1561, just before the Reformation swept Scotland's monasteries away, Inchaffray's income was assessed at 667 pounds, now the third lowest of the Augustinian abbeys in the kingdom. Five years before that, in 1556, the abbey had already been turned into a secular lordship for a Drummond, and the monastic life that had defined the island for three and a half centuries was finished.

The abbots of Inchaffray were political figures as much as religious ones. Maurice, who blessed the army at Bannockburn, carried the relics of St Fillan, a saint particularly associated with the Bruce family. Two centuries later, in 1514, the commendatory abbot Laurence Oliphant marched south with James IV's army and died at Flodden, the catastrophic defeat that killed the king and a generation of Scottish nobles in a single afternoon. Oliphant came from a notable Strathearn family, and his death in English mud is a small part of the larger ruin that Flodden inflicted on the country. James VI later visited the lay holder of the abbey lands, James Drummond, on 5 October 1601, and the property eventually passed to the Earls of Kinnoull, who held it as ordinary estate.

In 1816 a road was driven straight across the abbey site, demolishing most of what remained. The destruction is hard to picture from the surviving photograph of the ruins as they appeared in 1794: still substantial walls, a recognisable abbey footprint, monuments and burial markers. After the road came through, almost none of that survived. Today a single gable-end wall stands on private land, visible from the public road but not approachable. The ruins are a scheduled monument, the surrounding fields still drained by the abbey's own nine-mile ditch. The seal of Inchaffray, recovered late in the 13th century, sits in the British Museum, a two-sided pendant showing the abbey at its medieval height. The abbots who once ranked with Scotland's greatest churchmen are reduced to that single fact: one wall, one ditch, one small carved seal, and the memory of a blessing given the night before Scotland's most famous victory.