Fragments of antique capitals used upside down as bases of columns here and there, some columns of African marble in the chapel of St. Ippolito behind the High Altar, and a beautiful marble doorway with decoration of pagan character in low relief, at the entrance to the chapel of St. Aquilino, show that the church is partly composed out of the wreckage of the Roman city. The chapel last named, which opens off the ambulatory on the south, is of the sixth century, and has kept its ancient form. It is octagonal like the church, and is roofed with a shallow cupola. The circle of deep apertures high up, by which it is lighted, form outside those round-headed niches so familiar in later Lombard buildings. The Empress Galla Placidia is supposed to have founded this chapel, and to have intended to be buried there. A Christian sarcophagus, of late Roman workmanship, stands in a niche on the right hand of the entrance. But Galla Placidia lies in her gorgeous mausoleum at Ravenna. This sepulchre is said, however, to enclose the remains of her first husband, Athanulph, King of the Goths. Some mosaics in lunettes on either side of the apse date from the early days of the chapel—Christ with the Apostles, and the Shepherds feeding their Flocks. The sixteenth century tomb of St. Aquilino occupies the apse, which is decorated with frescoes of the Luinesque school. There is little else of interest in the church. In the ambulatory is a tomb of 1411, and above it a much restored painting of Madonna with SS. Stephen and Ambrose presenting to her members of the Robbiano family, and in the chapel of St. Ippolito, a tomb with the effigy of Antonio Conte, a priest of the church, who died in 1349, and the late fifteenth century monument of another of the same family, Giovanni Conte, who restored the chapel. The façade is of ornate late classic style, and the unfinished building on either side of the court in front was designed by Ricchini, a seventeenth century architect. An interesting view of the exterior, from the Piazza Vetra, on the north-east side, shows the enormous dome rising with incongruous effect, above the brick mass of the building, between four low towers of Lombard style, which survive from the eleventh or twelfth century reconstruction of the church after the great fires. The archway and towers in the main street just beyond San Lorenzo represent the old Porta Ticinese, built by the Milanese consuls in 1171, and restored by Azzo Visconte in the fourteenth century. The structure was newly restored in 1858. Upon the outer side of the arch there is a sculpture of Madonna enthroned with the Child, and St. Ambrose presenting to her a model of the city, with SS. Lorenzo, Eustorgio and Peter Martyr, standing around. Similar groups, now in the Museo Archeologico, were placed upon Porta Romana and Porta Orientale by Azzo. They are the work apparently of the Campionese followers of Giovanni di Balduccio of Pisa. [Illustration: THE OLD PORTA TICINESE.]