Before the Benedictines, the Scillies belonged to a confederacy of hermits. Celtic Christianity favoured solitude on small islands, and Scilly was the perfect refuge: remote enough for true solitude, navigable enough to be supplied, harsh enough to count as penance. King Henry I formalised the arrangement around 1120 when he granted the islands' churches in perpetual alms to Osbert, Abbot of Tavistock, and to his monk Turold, confirming the lands such as the monks or hermits held in the time of King Edward the Confessor. The hermits had been there first. The monks were the inheritors of someone else's solitude.

Pope Celestine III confirmed the holdings on 29 May 1193 by papal bull, listing in Latin a small empire of off-islands: St Nicholas (Tresco), St Sampson (Samson), St Elidius (St Helen's), St Theona (Tean), and the mysterious island called Nutho, possibly Nut Rock and the surrounding land, where remains of submerged hedges between it and Samson can still be seen at low tide. The wealth was modest but the prestige was substantial. Then in 1351 pirates destroyed most of the abbey property, and by 1367 the monks were petitioning King Edward III for special royal protection because the priory was almost destroyed and impoverished by mariners. Edward III granted it. The priory limped on but never recovered its scale.

Henry VIII's Dissolution of the Monasteries in the 1530s nominally ended the priory, but the records suggest it may have effectively closed earlier, drained by piracy and isolation. The stones did what abandoned monastery stones usually do: they became someone else's building material. Cottages absorbed them. Walls were repurposed. By the time Augustus Smith arrived in 1834 to take up his lease of Tresco, what remained was a roofless arch in a barren field. Smith made a deliberate choice. Rather than clear the ruins or build over them, he made them the focal point of his new house and garden. He aligned terraces to frame the arch. He planted shelterbelts to protect it. The monastery became architecture.

Today the remains of the priory sit inside the Tresco Abbey Gardens, a Grade II listed building and a Scheduled Monument under UK law. Visitors walk through the medieval arch surrounded by king proteas, Echium pininana, and South African pelargoniums. The contrast is not subtle. The arch was raised by people who believed they were preparing souls for eternity; it is now framed by plants from the southern hemisphere arranged for visual pleasure. The juxtaposition would have horrified the original monks. It might also have intrigued them. Benedict's Rule emphasized stability and the long view, and an arch that has stood for nine centuries while monasteries, pirates, dissolutions, and Empires came and went is the long view made stone.