Southern span 5
The chapel was dedicated to St. Thomas the Apostle, depicted in the keystone .
The fifth span contains several works of art:
The altarpiece by Bernardino Luini ;
two paintings with the Oration of Jesus in the Garden of Gethsemane by Lombard painters of the early seventeenth century from the Gallio Collection willed to the Fabbrica del Duomo (1687) ;
the seventeenth century statue of St. Isidoro the Farmer patron of Madrid, that at firs held a golden ear of wheat, is by Giovan Battista Maestri known as Volpino, baroque sculptor , and comes from the altar dedicated to that Spanish saint in the Odescalchi chapel of the destroyed Dominican church of St. Giovanni Pedemonte in Como.
The pedestal of the statue of St. Isidoro was made in 1852, designed by Giambattista Morelli, the engineer of the Fabbrica del Duomo.
The altarpiece by Luini known as the Raimondi altarpiece or the San Girolamo altarpiece was also called the Madonna of the Relief. It presents the Virgin and the Child among the saints: from left Girolamo as cardinal accompanied by the lion; Antonio of Padua with the lilies, Nicola of Tolentino also with the lilies and the sun on his chest, Agostino with the open book. There are also symbolic motifs: the eggs, the symbol of the Incarnation and Resurrection, and the flowers symbol of the divinity and humanity of Christ. The humanity is symbolized by the small white flower of the alyssum, a four-petal flower of the crucifer family, the divinity is symbolized by the carnation, because in the ancient Greek language the name of the carnation – dianthos – means the flower of God.
The kneeling donor can be identified as a canon of the Cathedral by the ancient red habit, but not as a cardinal, like some art historians have speculated.
The altarpiece has no certain chronology, for stylistic reasons it is dated around 1518.
The Raimondi altarpiece is documented at this altar in 1668, before it stood in the first northern span, near the Broletto. The Madonna delle Grazie by Andrea de Passeris now at that altar was painted in 1502 for this altar. The presence of St. Thomas Apostle in the keystone proves it: he is depicted holding the belt that Mary left him before being taken to heaven, according to legend.
The panels of the predella depict from left to right: St. Peter, St Jerome praying in the desert, St. John the Baptist in the center, then the funeral of St. Jerome, finally St. Paul.
The Luini board underwent numerous restorations: in 1804, in 1822, in 1851, then in 1887 it was transferred from a wooden panel to canvas by an expert such as Giuseppe Stefanoni with Luigi Cavenaghi.