“New” Virgil Opera Coming to Auction

From a Christie’s press release:

On 12 June 2013, Christie’s London will offer a newly discovered, deluxe copy of Opera by Virgil (70-19 B.C.) in the sale of Valuable Printed Books & Manuscripts (estimate: £500,000 – 800,000). The Aeneid is accepted as the foundation stone of western literature, and this copy is the earliest edition a collector could ever aspire to own.

Printed in 1470, within a year of the beginning of printing in Venice, it is the second edition, acknowledged to be textually superior. Its rarity is indicated in the fact that the last copy to come on the market was sold almost a century ago, in 1920. This newly discovered copy is complete and printed on costly vellum for a wealthy patron; the elegance of its page and the hand-painted decoration add to its resemblance to a Renaissance manuscript, and indeed, an earlier owner may have regarded it as a manuscript, perhaps contributing to its true identity not being recognised until now.

This book combines rarity with great aesthetic beauty but also represents a monumental moment in the history of printing.

… I can’t find mention of when this was ‘newly discovered …