An illuminated 14th-century manuscript containing what is believed to be the oldest surviving account of the legend of King Arthur and the knights of the round table was sold for £2.39m yesterday.
The Rochefoucauld Grail, an illustrated account of King Arthur, Merlin and the Holy Grail, was sold by Sotheby's in London.
More than 200 cows would have been needed to produce the vellum sheets for the three hefty volumes that contain 107 finely painted illustrations.
It was written in Flanders or Artois some time between 1315 and 1323 and probably produced for Guy VII, Baron de Rochefoucauld, head of one of the leading aristocratic families of medieval France.
Sotheby's specialist Timothy Bolton said: "This is one of the principal manuscripts of the first significant medieval work of secular literature."