In the dark ages, the island was used a seat of early Christian settlement. The child Jesus was believed to have visited the Island with his uncle, Joseph of Arimathea, who traded with the Cornish tin traders. Looe Island was already a place of pilgrimage for early Christians before the creation of this story and a small thatched roofed chapel was built there during this time.
In the later medieval period, the island came under the overall control of Glastonbury abbey, with the Prior of Lammana being directly responsible for its governance; the island's chapel was under the care of two Benedictine monks until 1289 when the property was sold to a local landowner. The priory was replaced by a domestic chapel served by a secular priest until the dissolution of the monasteries in 1536 when it became property of the Crown. From the 13th to the 16th centuries it was known as St Michael's Island but after the dissolution of the monasteries, it was rededicated in 1594 as St George's Island.
The cache itself is quite sneaky so may take some looking, please be stealthy as it is hidden in plain sight and can be busy in the summer months.