An upcoming auction at Christie's has served as a reminder of an exceptional book collection owned by an eccentric British aristocrat.
William John Cavendish Cavendish-Scott-Bentinck, 5th Duke of Portland was born in 1800. After home-schooling and an army career he returned to the estate of Welbeck Abbey which he had inherited and made huge developments at.
Aside from huge walls, a grand riding house (for the Duke's 100 horses) and more surprisingly a roller-skating rink for his staff, Bentinck's most famous projects were underground.
In keeping with the Duke's famous shyness and introversion (only his valet was allowed to see him in his quarters, he avoided meeting people at almost any cost and conducted his business in writing alone) he had a maze of underground tunnels and rooms constructed.
The tunnels ran to 15 miles long or more - there was an unconfirmed claim that one ran all the way to Worksop station - and included a 76 metre long library where the family's collection of books was kept.
The Bentincks were keen collectors of texts and periodically books with the family name appearing in the provenance appear at auction, with two auctions in late 2010 at Christie's providing examples:
A 15th century decorated manuscript on vellum version of the Book of Hours in Dutch sold for £17,500 ($27,878). It is an impressive work, presenting six large puzzle initials in red and blue with extensive flourishing in red and purple to upper and side margins.
More spectacular still was a 16th century Psalter in the German translation of Martin Luther.
The illuminated calligraphic manuscript on vellum and paper was created by Nicolaus Selneccer (1530-1592) for John VII of Oldenburg, and described as a "magnificent masterpiece of calligraphy and micrography in its original binding" by the auctioneer.
The Psalter nearly doubled its top estimate of £80,000 to sell for £151,250 ($239,126). Both works are associated particularly with Charles Aldenburg Bentinck (1810-1891).
The most valuable work of the whole collection, however, which is the one going under the hammer this month, is a more modern work: John James Audubon's The Birds of America.
Published in four volumes, the 'double-elephant' broadsheets edition of 435 hand-coloured engravings was extremely limited.
It is one of only 13 editions currently in private hands, whilst a further 107 copies remain in museums and libraries, and the world record price for a book was set by one of the copies at £7.3m ($11.5m) through Sotheby's. Christie's is offering the book with a $7m-10m listing.
The copy may have been acquired first by Portland's father, who had a keen interest in natural history.