A pair of alabaster mourners from the tomb of Jean de France (1340-1416), brother of French king Charles V, are to go on sale at Christie's on November 8. They are to auction as a single lot and carry an estimate of $674,250-$1.1m.
Jean de France was one of the great patrons of the medieval period, commissioning works of art that included the famous Tres Riches du duc de Berry, a book of hours in the gothic style by the Limbourg brothers.
Much of his collection can now be found in the British Museum in London.
It was customary during the medieval period for members of the French royal family to design their own tombs, and de France appointed sculptor Jean de Cambrai to the task.
The initial plans included a life size figure carved in marble alongside a procession of 40 mourners.
Jean de France died in 1416, and the tomb was not completed until 1457. The mourners date from this later period, having been carved by Paul Mosselman in around 1450-1453.
They feature expressive faces and flowing robes - in contrast to the earlier versions which were of a much simpler design.
The tomb lay in the choir of Saint Chappele in Bourges until the church was demolished in 1756. It was later vandalised during the French revolution.
Isabelle Degut, director of the sculpture department at Christie's, commented: "Having these most remarkable sculptures available on the art market is a significant milestone for all collectors of medieval art.
"Both mourners have remained within the same French collection for more than two centuries."
A small alabaster mourner from a Burgundian tomb, dating to the same era, but lacking the provenance of the Jean de French sculptures, sold for £18,000 ($28,881) against an estimate of £10,000-15,000 ($16,044-24,066) at Sotheby's London in 2003.
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