Art: HIDDEN MASTERPIECE: Kassel's Rembrandt

THE industrial city of Kassel, Germany, is off the tourist track, and its art museum has only 60,000 visitors a year (as against 200,000 each for Munich and Cologne). Yet Kassel's Gemaeldegalerie can boast of one of the world's most brilliant collections of early German and Flemish paintings, topped by no fewer than 19 Rembrandts. Kassel can thank the art-loving Landgrave Wilhelm VIII, who ruled Hesse from 1751 to 1760. As a youth, Wilhelm did military service in the Low Countries, fell in love with Flemish art, and got in the habit of collecting it. Wilhelm's finest trophy was Jacob Blessing...