The first painting on the right wall of the nave represents the sermon of St. James the Greater (first century AD), one of Jesus’ disciples and, according to tradition, propagator of the Gospel in Spain. The Sanctuary of Santiago was built after one of his apparitions, soon becoming one of the main destinations of medieval pilgrimage. The artist depicted the saint with his traditional symbols: the cane and the shell. Shells where gathered by pilgrims arriving in Santiago who, in order to prove that they had completed the pilgrimage, used to reach the western coast of Spain.
A crowd of men, women and children, gathered in front of a classical building, raptly listen to the saint’s fervent words. St James was known for his rebellious character, and was called "Son of Thunder" by Jesus. A group of angels observe the scene from above while reflections of golden beams shine through dark clouds, symbolizing divine light. The painting, made by Giuseppe Nicola Nasini in the last decade of the seventeenth century, reveals the influence of Pietro da Cortona’s Baroque style. It was placed on the second altar of the right wall, which once belonged to the Tondi-Ugurgieri family.