Holding the remains of the Holy Trinity Monastery, this privately-owned island is easily viewed by car or bus from its striking shoreline, abundant with natural beauty. Holy Trinity Monastery (Trinity Abbey), built in 1214 by the Order of Premontre is famed for the creation there of a monastic work which chronicles local Irish affairs between the years of 1014 and 1570.The west gable of the Abbey remains in remarkable condition. It displays a pointed window over a mutilated doorway. Fragments of stone slabs with ornate and elaborate carvings are strewn about the adjoining graveyard (where Una and Tomas are said to be buried). Also said to be buried here are the remains of noble chieftain O'Reilly and many of his family members. Splendid monuments once marked their graves. Surrounded by a circular fosse planted with tall white thorns, the monastery and its cemetery at Trinity Island would have been protected from wind and water, its monks sheltered from cold winds blowing off the lake.