Devotion, Demons and Daily Life in the 15th century. The Hours of Catherine of Cleves is arguably the most beautiful and interesting manuscript ever to be produced in the Northern Netherlands. It was illuminated with spectacular miniatures and borders in glistening gold and sumptuous colors around 1440 for Catherine of Cleves, Duchess of Guelders, by an exceptionally gifted but anonymous artist, named after this, his masterpiece.