This medieval ring is set with a much earlier sapphire intaglio, probably carved in the Greek World around the first century BC. In the Middle Ages, between the 12th and 14th century, ancient gems were frequently re-set for use as personal seals, authenticating letters and legal documents. Roman or Hellenistic images of gods or mythological figures were not so much misunderstood as re-interpreted in a Christian framework. A Ptolomaic princess such as the one on this seal, might therefore be used to symbolise the Virgin Mary, often shown with a veil over her head. In medieval Constantinople, gemstones engraved with subjects from classical antiquity were sometimes labelled with the names of Christian saints such as an amethyst portrait of the Roman emperor Caracalla which was recut and renamed as Saint Peter.
The inscription around the bezel of the ring: 'Tecta lege, lecta tege' is translated as 'Read what is written, hide what is read' and shows the ring's use as a personal signet. The sapphire is set in an open-backed mount, allowing it to touch the skin of the wearer. Direct contact of the stone with the skin was believed to convey a medicinal or amuletic benefit. A lapidary describing the powers and uses of gemstones, written by Marbode, the eleventh century bishop of Rennes claimed that sapphires had the power to dispel envy, detect fraud and prevent witchcraft.
This ring forms part of a collection of 760 rings and engraved gems from the collection of Edmund Waterton (1830-81). Waterton was one of the foremost ring collectors of the nineteenth century and was the author of several articles on rings, a book on English devotion to the Virgin Mary and an unfinished catalogue of his collection (the manuscript is now the National Art Library). Waterton was noted for his extravagance and financial troubles caused him to place his collection in pawn with the London jeweller Robert Phillips. When he was unable to repay the loan, Phillips offered to sell the collection to the Museum and it was acquired in 1871. A small group of rings which Waterton had held back were acquired in 1899.