In the year 1260, Nicola Pisano, the sculptor who initiated the revival of classicizing ideals that would later form a major component of Italian Renaissance art, created a remarkable and unusual monument for the Baptistry of Pisa, a hexagonal pulpit supported by seven colorful columns and displaying on its parapet five visually compelling narrative reliefs; several years later he designed a second pulpit, this time for the cathedral of Siena. Toward...