Signet rings, engraved with a coat of arms, owner's initial or the mark used by a merchant to identify his goods are one of the the most common types of surviving medieval or Renaissance rings. The engraved bezel of the ring was pressed into sealing wax and this was then fixed onto a letter or deed. They were made of gold, silver or bronze, depending on the means of the owner and continued to be widely used until the 18th century when they were largely replaced by fob-seals, worn on the watch chain.

Signets with a single crowned letter are most often found in silver or brass. It is much more unusual to find a gold ring which bears an initial rather than a coat of arms or heraldic device. W and I are the letters which are seen most frequently, possibly indicating commonly used names such as William, James or John. The small star engraved on one shoulder of the ring indicates the top of the seal.

This ring forms part of a collection of 760 rings and engraved gems from the collection of Edmund Waterton (1830-87). 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.