Beloved by Christ, the youthful John was present at the Crucifixion. Here Piero depicts the Apostle in old age, reflecting on his Gospel or the Book of Revelation. Piero invested each saint with iconic presence, and his attention to detail is meaningful: along the hem of John’s robe, light catches a border of pearls, rubies, and aquamarines, the kind of gems he created miraculously from pebbles.