 The history of Lihou is closely linked to the history of Guernsey in particular and the Channel Islands in general . The earliest evidence of habitation are Mesolithic era objects recovered from archaeological digs of the 1990s , along with Neolithic era tombs on the nearby mainland . The recorded history of Lihou began in 933 AD when the Channel Islands were seized from Brittany by the ruler of Normandy . Lihou and the nearby Neolithic tombs were traditionally believed to have been meeting places for local witches , and fairies . This led to conflict with church authorities , especially when a priory was established on Lihou , dedicated to St. Mary ( known locally as Our Lady of Lihou ) . A number of dates have been suggested for the establishment of the priory , with estimates ranging from as early as 1114 , to as late as 1156 . Records suggest that the priory was an arriére @-@ fief of the Benedictine abbey of Mont St. Michel under whose authority it operated . Ownership of the island was granted to the abbey by Robert I , Duke of Normandy , in the early part of the eleventh century . The priory is thought to have been constructed with contributions from the islanders , who appear to have been fairly affluent at the time . 
