‘Miracle’ cache of letters written by French scientist who died in ill-fated La Pérouse mission give personal account of 1785 voyage

As he prepared to climb the scaffolding to be publicly executed by guillotine on 21 January 1793, Louis XVI is reported to have asked: “Is there news of Monsieur de la Pérouse?”

He was referring to Jean-François de Galaup, the count of Pérouse, a naval officer and navigator whom the French king had dispatched in 1785 on a round-the-world scientific mission to rival discoveries made by the English explorer Captain James Cook.

Book containing early versions of the Merlin and Grail legends has remained in private hands for 700 years

In one illustration, painted on vellum and decorated with gold leaf, the sorcerer Merlin is depicted as a powerful shape-shifter who has transformed into a talking stag. In another, the Knights of the Round Table are shown returning, victorious, from battle.

The illustrations appear in one of the earliest manuscripts to tell the tale of King Arthur and the search for the holy grail – a richly illuminated medieval tome which, for more than 700 years, has been in private hands.