The Tau cross, possibly derived from the Egyptian ankh, is the symbol of St Anthony Abbot, an Egyptian hermit and swineherd of the third century AD. The Tau cross is said to represent the crutch which he used to control his herd. The resemblance of the Tau to a cross led to it being ascribed a mystical significance.

St Anthony was believed to cure ergotism, or St Anthony's fire, and to protect the faithful against pestilence and poisoning. He was the patron saint of the poor and sick and of knights, butchers and brushmakers. A ring bearing the symbol of St Anthony would confer the protection of the saint on the wearer. It may also have been used by members of religious orders dedicated to St Anthony, for example the military order of the Knights of St Anthony, founded by Albert II of Bavaria in 1382 before his proposed campaign against the Turks. It is also possible that some rings bearing this emblem may commemorate a pilgrimage to the church of St Antoine de Viennois, Dauphiné, France where the saint's relics were placed after their transfer from Constantinople in the eleventh century.

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.