In the old abbey gardens at Tresco is a curious stone, about four feet long, two feet wide, and six inches in thickness, in an upright position. Near the top are two holes, one above the other (one being somewhat larger than the other), through which a man might pass his hand. It is supposed to be an old Druidical betrothal or wishing-stone, and used before the monks built the abbey at Tresco. Young people, engaged to be married, would pass their hands through the holes, and, joining them together, would so plight their troth. As a wishing-stone, or to break a spell, a ring woudl be passed through the holes with some incantations. - J.C. Tonkin's Guide to the Isles of Scilly.
M. A. Courtney
The Folk-Lore Journal, Vol. 5, No. 1. (1887), pp. 14-61.
"Close to the west of the church's north west corner, the scheduling includes a prehistoric ritual holed stone, visible as an upright slab 1m high and 0.5m wide, roughly shaped to give parallel sides and a flat upper edge; below the
top edge, the slab is perforated by two round holes, each approximately 0.08m in diameter and 0.1m apart, one above the other on the slab's midline. The slab was found on Tresco or Bryher at the beginning of the 20th century and was erected in its present location to serve as a feature in the Tresco Abbey Gardens."
The priory has an early Christian slab that is the earliest evidence for Christianity in the Scillies, and even after the dissolution of the Priory, people were buried in its grounds until the early 19th century.
"The holed stone near the church is one of four examples from Scilly of this very rare class of prehistoric ritual monument whose distribution is concentrated in the western tip of Cornwall and Scilly; although not in its original position, its present setting near the early Christian memorial slab and the upright gravestones in the church's post medieval cemetery gives a good illustration of the long period over which upright stone slabs have held a strong religious and funerary significance."