Illuminated initial from a late 14th century Book of Hours - estimate of £20,000-30,000 at Forum Auctions on November 25

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It is thought to have been decorated c.1390 by the Master of the Calderini Pontifical – an anonymous artist working between L’Aquila and Rome during the years of the Great Schism that followed the removal of the papacy from Italy to France.

He takes his name from the inscription and heraldry that appears in a lavishly decorated manuscript in the Houghton Library at Harvard.