Passing behind the High Altar, through the crypt or under choir, which was built in 1537 and is supported on columns once forming part of the cloister of the adjoining convent, and through a vestibule with remains of old frescoes on the walls, we come to the Capella di S. Pietro Martire—the Portinari Chapel—the exterior of which has been already described. In this rich and complex structure, rectangular below and rising by the grand curves of wide-spanned arches to a lofty sixteen-sided cupola, in the delicate arcade and parapet running round it high up, in the beautiful terra-cotta decoration of frieze and cornices, the sculptured arabesques of the pilasters, the frescoes in spandril and arch, we recognise the new spirit of the Renaissance. The architecture is of Tuscan inspiration, though certain details, such as the point still visible in the rather ornate windows, are indicative of Lombard taste. The chapel, which in form recalls the Pazzi Chapel in Florence—though it lacks the perfect purity and restraint of that wonderful building—is always supposed, though without any positive evidence, to be by Brunelleschi’s pupil, Michelozzo. The general design may be regarded as certainly Michelozzo’s, and much also of the ornamentation, especially the charming stucco frieze of dancing angels, light graceful forms instinct with winged motion and linked by a long chain from which depend great bells of fruit and foliage. The same great bells or tassels with fat _putti_ swinging on them, compose the delightful arabesques on the pilasters. To Vincenzo Foppa, chief of the early Milanese school of painters, was entrusted the fresco decoration of the chapel. The four Fathers of the Church, in tondi in the spandrils, figures of a robust and quiet realism, full of a naturally-expressed dignity and fresh and decorative in colour, are some of his finest work. The other frescoes, four large scenes representing scenes from the life of Peter Martyr—the Saint preaching at Florence; confounding a false miracle-worker at the altar; tending a youth who has fallen from the top of a building and whom he has miraculously saved from death; and being stabbed to death by heretics—are Foppa’s design and in part his work, but they have been much restored, and in their present state are hardly worthy of him.