Accompanied by documentation from the Portable Antiquities Scheme and British Museum stating that this ring was found whilst metal detecting on cultivated land on 1st-30th November 2013 in Emsworth, Hampshire, UK. It is recorded with the Portable Antiquities Scheme under reference number HAMP-EBA980 and disclaimed under the Treasure Act, reference number 2014 T11.
Sapphires were a favourite choice in the Middle Ages, though so rare that they were reserved solely for royalty, upper nobility and certain high ranking clergymen. Sapphires were thought to be imbued with magical powers such as protecting the wearer from the effects of poison, preserving chastity, keeping the peace and curing snake bites.
This is an exceptional Museum quality example of a Medieval finger ring, see The Victoria and Albert Museum, London, object number 642-1871, for a ring of similar style.