Only seven other dated examples of such ivory vessels are known to exist, and all are in museums.
Marcus Fraser, director of Sotheby's Islamic and Indian department, said: "This box is definitely one of the major Islamic discoveries in living memory.
"The astonishing quality, beauty, rarity and art-historical significance of this box make it one of the most outstanding Islamic works of art ever to come to auction."
Nicholas Shaw, an expert in the auction house's Islamic department, said he took a "sharp intake of breath" when he was first sent photographs by the curious owner.
"I could hardly believe it. Pieces such as these are so rare and I couldn't imagine that one could turn up in Yorkshire," said Mr Shaw.
The vendor, who does not wish to be named, had attended the sale where it was bought with his uncle in 1947, when he was 12.
It was part of a job lot with other ornamental items in the sale of contents of Hickleton Hall, near Doncaster - the former home of the first Earl of Halifax - and the uncle bid just pounds 9- 19-6d.
The current owner inherited the box when his uncle died, and kept it in the hall of his home in Yorkshire.
Intrigued by its history, he took it to experts at the BBC's Antiques Roadshow last year. They recommended he contact auctioneers.
The box is one of a small surviving group of vessels made in the late 10th and early 11th century to glorify the lifestyles of the great Moslem rulers in the Spanish city of Cordoba. They appear to have been made exclusively for the ruling family.
The box is a star lot in an auction on 15 October during Sotheby's Islamic week.Reuse content