Sir John Mandeville was a celebrated, but fictitious, medieval English traveller, whose fantastical writings became popular across Western Europe. This illustration accompanied a Czech translation of Mandeville’s Travels. It shows a group of astronomers standing on Mount Athos in Greece, known as ‘Holy Mountain’, studying the stars with their astrolabes and quadrants. Others are shown writing strange characters in the dust with their sticks, perhaps one of the mysterious foreign alphabets described by Mandeville. Shown here: f. 15r