Front Cover for a Gospel Book of French Cardinal Jean La Balou (1421-1491), c. 1467-1468. Scenes from Christ?s infancy decorate this cover that once adorned the front of a gospel book. It is made up of a series of silver plaques held together by gilt-silver borders. The plaques are engraved, and the resulting fine lines or depressions have been filled with a silver sulfide alloy, lustrous black in colour, in a technique called niello. It is one of the finest examples of this decorative technique for which Florence was renowned in the 15th century. This cover and its manuscript once belonged to the French cardinal, Jean La Balou, who was jailed in 1469. He presented his gospel book to Pope Paul II as a gift, perhaps in the hope of receiving his freedom. The gospel book, of which its two covers have survived (the back cover is in the Minneapolis Institute of Arts), remained in the papal apartments until the end of the 18th century, perhaps leaving when Napoleon?s troops held the Vatican.