The French or Flemish 16th century silver gilt and enamel salt had been among 500 Renaissance and Baroque treasures - believed to be worth in excess of £10m - donated to the Oxford museum in 2012 by the late silver dealer Michael Wellby.
However, research into its provenance led the Ashmolean to discover that the salt had belonged to the Jewish collector Emma Budge of Hamburg.
Together with her husband Henry, who had made his fortune financing American railroads, she assembled a huge collection for their lavish home Budge Palais. Shortly after the couple died, the estate was looted by the Nazi authorities in 1937 and over 2000 pieces dispersed in a forced sale by the now-defunct Berlin auction house Paul Graupe.
Another of these pieces, a rare Meissen harlequin figure, was recently found in the collections at the Victoria and Albert Museum. Given to the institution in 1984, it was restituted to the heirs of the Budges earlier this year and consigned to Bonhams where it sold for £65,000.
The salt, also returned earlier this year, was included in Sotheby's Treasures sale on July 8 in London. Measuring 14in (35cm) high and surmounted by a warrior finial, it would once have taken pride of place at a 16th century refectory table. Large salts were positioned to the right of the most important person, marking the spot above or below which guests were seated according to rank.
As salt had a religious element, it was not unusual for the containers (frequently given as baptismal gifts) to carry religious imagery.
Particularly striking on this example are two diamond shaped basse-taille enamel panels depicting The Annunciation and Coronation of the Virgin. They had been mounted previously on another object and dated to the 14th century. Further embossed and chased panels depict the Nativity and Resurrection.
Guided at £300,000-500,000, it sold to an anonymous buyer on the phone after a battle with a bidder standing in the room.
The buyer's premium at Sotheby's was 25/20/12%.